Abstract

A novel embedded ultra-long period fiber grating (EULPFG) based on a graded index multimode fiber (GI-MMF) is proposed for temperature measurement. Due to the small RI difference of the modes near the GI-MMF self-imaging point, the resonant peak of transmission spectrum is wavelength-insensitive to refractive index (RI), strain and bending. However, the sensor is sensitive to temperature. The experimental results show that the temperature sensitivity of the EULPFG is 90.77 pm/°C. The sensitivities of other physical parameters are suppressed, and the suppressed sensitivities are at least one order of magnitude less than those of similar sensors. The EULPFG with anti-interference from other parameters is expected to be used in ocean monitoring systems to measure the temperature of the seawater.

© 2021 Optical Society of America under the terms of the OSA Open Access Publishing Agreement

1. Introduction

With the melting of glaciers and the rise of sea level caused by global warming, the living environment of human beings, animals and plants will be seriously threatened. Ocean as a key area for regulating climate change, accurate monitoring of its temperature is crucial. In recent years, due to the development of optical fiber processing technology, optical fiber sensors have been widely studied and applied. In ideal environment, optical fiber temperature sensors based on long period fiber grating (LPFG) [1], fiber Bragg grating (FBG) [2] and Mach–Zehnder interferometer (MZI) [3] have been widely studied and achieved remarkable results. However, in the actual measurement, the measurement of single target parameter is often accompanied by the interference of a various factors. It is a research focus to eliminate the cross-sensitivity between multiple parameters so as to achieve accurate measurement.

In existing studies, simultaneous measurement of multiple parameters is a common method to avoid sensitivity cross-talk. For example, Zhao et al. used femtosecond laser and hydrofluoric acid etching method to write FBG into pure quartz grating [4]. Because the light has dual characteristics of energy and wavelength, the simultaneous measurement of temperature and RI is realized. However, the production cost of the sensor is high and the demodulation is complex. Liu et al. proposed a sensor based on the MZI cascaded with FBG for simultaneous measurement of temperature and strain [5]. Pang et al. realized the simultaneous measurement of temperature and surrounding RI by superimposed coated the LPFG and FBG [6]. These sensing elements are formed by combining multiple sensing units, which have the disadvantages of complex structure and difficult preparation. In 2020, Zhang et al. prepared novel sensors based on the MMF embedded LPFG for simultaneous measurement of double physical parameters [7,8]. These sensors have the advantages of simple structure, low cost and easy preparation. Therefore, the sensor with simple structure and low cross-sensitivity has a good application prospect. In 2019, Yao et al. proposed a strain insensitive temperature sensor based on a few-mode double-concentric-core fiber [9]. The sensitivities of temperature and strain are 52.79 pm/°C and 0.23 pm/µε. In the same year, Song et al. used DNA-Cetyltrimethyl ammonium solid film deposited on micro-tapered fiber to achieve high sensitivity temperature measurement [10]. The elastic film can effectively reduce the influence of strain on the sensor. These sensors have low strain cross-sensitivity (4.36×10−3 °С/µε and 7.78×10−3 °С/µε), but they cannot eliminate the influence of other physical parameters on temperature measurement.

In this paper, a novel sensor consisting of periodic alternating splicing of the SMF and GI-MMF is fabricated and used to accurately measure temperature. The doping of germanium in the core increases the thermal-optic coefficient of fiber. Therefore, the proposed sensor has a good temperature sensitivity. By monitoring shift of resonant wavelength, the temperature sensitivity of 90.77 pm/°C is obtained. The interference of the RI, bending and strain is suppressed to a certain extent, and the corresponding sensitivities are −2.24 nm/RIU, −2.25 nm/m−1 and −5.45×10−2 pm/µε. In particular, the sensitivities of the RI and bending are one order of magnitude lower than that of the general LPFG, and the cross-sensitivity of strain-temperature is −6.00×10−4 °С/µε. The sensor is expected to steadily measure temperature in various environments, such as oceans, buildings and so on.

2. Preparation method and principle of operation

2.1 Preparation method

As shown in Fig. 1(a), the GI-MMF with a fixed length (700 µm) are orderly embedded into the SMF to form the EULPFG. The cladding diameter of the SMF (9/125 µm) and GI-MMF (50/125 µm) is same but the core diameter is different. The combination of a segment GI-MMF with 700 µm and a segment SMF with 1000 µm is defined as a period. The preparation process of the sensor is shown in Fig. 1(b1)-(b3). Two fibers with smooth end face are spliced together by arc discharge. The splicing parameters of the fusion splicer (FSM-87c, Fujikura Co., Ltd.) are as follows: Discharge intensity: +15 bits; Discharge time: 3000 ms. Then, the spliced fiber is fixed by fiber clamp and the upper CCD is used to obtain clear splicing points. The fiber segment with different lengths is obtained by moving the fiber cleaver located on the displacement platform. The schematic diagram of the preparation device is shown in Fig. 1(c). By the microscopic imaging system, the average length error of the SMF and GI-MMF (about +4.49 and +0.55 µm) are obtained. Small splicing error avoids the deterioration of contrast ratio and shift of resonance wavelength. Meanwhile, the sensor has high mechanical strength and stable response to temperature, strain and RI because the external shape of the sensing region is not changed.

 figure: Fig. 1.

Fig. 1. The schematic diagram of (a) the sensing structure; (b) preparation process of the sensing structure; (c) preparation device and microscopic images.

Download Full Size | PPT Slide | PDF

2.2 Principle analysis

The RI distribution of the GI-MMF has a parabolic form. The relationship between the RI distribution and the radius can be described as [11]:

$${n^2}(r )= n_1^2 - ({n_1^2 - n_2^2} ){\left( {\frac{a}{r}} \right)^2},a < r$$
where, ${n_1}$ and ${n_2}$ are the RI of the core and cladding, r is the core radius and a is the distance from the fiber core axis. Figure 2 depicts the light field distribution profile of the step index multimode fiber (SI-MMF) and GI-MMF with the same numerical aperture (NA=0.2) and transmission distance (Z=700 µm). Due to the drastic variation of the RI distribution on the splicing ends of the two fibers, the direct coupling loss between the SMF and SI-MMF is large. The energy in the SI-MMF core is rapidly reduced with the increase of transmission distance. Different from the SI-MMF, the light in the GI-MMF will all return to the fiber core after transmitting a certain distance, which is called the self-imaging phenomenon, as shown in Fig. 2(c).

 figure: Fig. 2.

Fig. 2. The diagram of the light field distribution of (a) the SI-MMF; (b) the GI-MMF; (c) the core energy ratio along the transmission distance.

Download Full Size | PPT Slide | PDF

The distance between the self-imaging points of the experimental GI-MMF is 600 µm. In other word, splicing loss and coupling efficiency of the EULPFG are optimized in near 600 µm. However, since there is no phase difference between the modes at the self-imaging point, the grating cannot be formed [12]. Therefore, the length of 700 µm is selected to provide a certain phase difference between the two modes.

The phase matching condition for the formation of the EULPFG is:

$${\mathrm{\lambda }_{res}} = [{n_{co}^{eff} - n_{cl}^{eff}(r )} ]\mathrm{\Lambda }, $$
where ${\mathrm{\lambda }_{res}}$ is the resonant wavelength, $n_{co}^{eff}$ and $n_{cl}^{eff}(r )$ represent the effective RI of the core and cladding, and $\mathrm{\Lambda }$ is the period length of the EULPFG.

The temperature sensitivity of the EULPFG can be expressed as [13]:

$$\frac{{d{\lambda _{res}}}}{{dT}} = \left( {\frac{{dn_{eff}^{co}}}{{dT}} - \frac{{dn_{eff}^{cl,m}}}{{dT}}} \right)\mathrm{\Lambda } + (n_{eff}^{co} - n_{eff}^{cl,\; m})\frac{{d\mathrm{\Lambda }}}{{dT}}$$
where the first term on the right side represents the contribution of the thermal optical effect of the fiber to the temperature sensitivity, and the second term is the contribution of the thermal expansion effect. Generally, the thermal expansion effect of the fiber is negligible, because the thermal expansion coefficient is much lower than the thermal-optic coefficient. The doping of germanium in the fiber core results in the increase of the thermal-optic coefficient [14]. In our experiment, the NA of the GI-MMF is larger than that of ordinary communication fiber (NA=0.12). Therefore, the content of germanium doping in the core is higher. When the temperature rises, the effective RI difference between the core and the cladding changes dramatically under the action of thermal-optic effect, resulting in the wavelength shift of the resonant peak to longer wavelength. Therefore, the EULPFG is sensitive to temperature.

In the numerical simulation, Rsoft software is used to simulate the distribution and transmission of light in the fibers. The core/cladding diameters of the SMF and GI-MMF are the same as those used in experiment. The transmission spectra of the EULPFG with different GI-MMF and SMF lengths are shown in Fig. 3(a) and (b). Consistent with the theory, when the 600 µm GI-MMF is embedded in the LPFG, the grating cannot be formed. And the length of the GI-MMF is farther from the self-imaging point, the insertion loss of the resonant peak is larger. With the increase of the SMF length, the contrast ratio of the resonant peak increases first and then decreases and the resonance peaks shift to longer wavelength. The simulated light field distribution and spectrum evolution are plotted in Fig. 4. The insertion of 700 µm GI-MMF causes the light in the core to partly leak into the cladding. However, due to the strong energy near the self-imaging point of the GI-MMF, most of the light still remains in the core, resulting in low insertion loss of the sensor. The distribution of output light field is obtained by electric field scanning, and coupling mode of the model at the resonance wavelength of 1438.0 nm is $L{P_{03}}$. The reliability of the simulation provides a strong theoretical support for the implementation and measurement of the experiment.

 figure: Fig. 3.

Fig. 3. The transmission spectra of the EULPFG with different (a) GI-MMF lengths; (b) SMF lengths.

Download Full Size | PPT Slide | PDF

 figure: Fig. 4.

Fig. 4. The diagram of (a) light field distribution; (b) simulated spectrum evolution of the EULPFG.

Download Full Size | PPT Slide | PDF

3. Experimental results and discussion

3.1 Experimental results

The experimental spectrum evolution of the EULPFG is shown in Fig. 5. Due to the imperfection of the experimental operation, the transmission spectra between the simulation and the experiment are slightly different. When the phase matching condition is satisfied, a dominant resonance peak appears at 1418.2 nm in the transmission spectrum. The insertion loss and contrast ratio of the resonant peak are −4.33 dB and −34.62 dB, respectively. The high contrast ratio and narrow bandwidth (6.8 nm) ensure accurate measurement of physical parameters through wavelength demodulation.

 figure: Fig. 5.

Fig. 5. The diagram of experimental spectrum evolution of the EULPFG.

Download Full Size | PPT Slide | PDF

Figure 6 shows the integrated measuring device, including a thermostat, a super-continuum (SC) source, an optical spectrum analyzer (OSA), two fiber clamps and two controllers. It is used to measure temperature, strain, refractive index (RI) and bending. The sensing structure is placed in the middle and both ends are fixed by clamps. The SC (YSL Photonics, China) light and OSA (AQ6317b, Agilent Tech. Inc.) are connected at both end of the fiber to obtain the change of transmission spectra. The thermostat provides a precise and controlled heat source and an operating platform for the RI measurement. The L-shaped plate above the operating platform and the right fixed end of the fiber are controlled to apply the curvature and strain by two controllers, respectively. In addition, the thermostat is required to be removed during bending measurements to provide a space for bending.

 figure: Fig. 6.

Fig. 6. Schematic diagram of the integrated measuring device.

Download Full Size | PPT Slide | PDF

In the temperature measurement, the sensing structure is horizontally placed on the thermostat, and a thermal cover is pressed on the structure to prevent heat diffusion. The transmission spectrum is recorded every 10 °C from 30 °C to 150 °C. As can be seen from the illustration in Fig. 7, the resonant peak appears obvious red shift with the increase of temperature. By linear fitting between the wavelength and temperature, the temperature sensitivity of the sensor is 90.77 pm/°C, which is higher than that of general sensors [15,16].

 figure: Fig. 7.

Fig. 7. The change of transmission spectra under the different temperatures and the linear fitting between the wavelength and temperature.

Download Full Size | PPT Slide | PDF

Subsequently, in order to verify the influence of other parameters, the sensitivities of the RI, strain and bending are also measured. At the room temperature, the RI sensitivity of −2.24 nm/RIU is experimentally obtained by changing the external RI environment (1.333-1.437) of the sensing structure. The contrast variation of resonance peaks with the RI changes are inserted into Fig. 8(a). When the external RI is 1.437, the resonance peak disappears.

 figure: Fig. 8.

Fig. 8. The variation of resonant peak and linear relationship between (a) the RI and wavelength; (b) the strain and wavelength; (c) the curvature and wavelength.

Download Full Size | PPT Slide | PDF

The fiber clamp at the right end moves a distance of $\Delta L$, and the axial strain of the fiber can be calculated by formula: ${\varepsilon } = \frac{{\Delta L}}{L}$. The distance between the two clamps is L (L=30 cm). The transmission spectrum is recorded at a step of 167 µε from 0 to 1670 µε, as shown in Fig. 8(b). The strain sensitivity is −5.45×10−2 pm/µε, which is two orders of magnitude less than that of the similar sensor [17,18]. The experimental results show that the sensor is almost unaffected by strain.

Finally, the bending sensitivity of the sensor is measured. The fixed drop value ($\Delta d$) of the L-shaped plate is 0.5 mm, and different curvatures can be obtained by calculation [19]. As shown in Fig. 8(c), with the increase of curvature, the transmission spectrum shows slightly blue shift, and the bending sensitivity is −2.25 nm/m−1 in the curvature range of 0-1.247 m−1.

3.2 Discussion

In the EULPFG, the sensitivity of the strain, bending and RI can be expressed as [20,21]:

$$\frac{{d{\lambda _{res}}}}{{d\varepsilon }} = \lambda _{res}^m \cdot {\gamma ^m} \cdot ({1 + \mathrm{\Gamma }_{strain}^m} )$$
$$\frac{{d{\lambda _{res}}}}{{d\mathrm{\Lambda }}} = \frac{{{\gamma ^m}}}{{n_{eff}^{co} - n_{eff}^{cl,\; m}}}$$
$$\frac{{d{\lambda _{res}}}}{{dn}} = \lambda _{res}^m \cdot {\gamma ^m} \cdot \mathrm{\Gamma }_{RI}^m$$
where $\mathrm{\Gamma }_{strain}^m$ and $\mathrm{\Gamma }_{RI}^m$ are the strain/RI-dependent waveguide dispersion coefficient, respectively. ${\gamma ^m} = \frac{{d{\lambda _{res}}}}{{d\mathrm{\Lambda }}}(n_{eff}^{co} - n_{eff}^{cl,\; m})$ is the dispersion coefficient of the fiber. It can be seen from formulas (4) – (6) that ${\gamma ^m}$ is crucial for the sensitivity of strain, bending and RI. To determine the characteristic of the ${\gamma ^m}$ factor, the relationship between the resonance wavelength ${\lambda _{res}}$ and the period $\mathrm{\Lambda }$ is calculated and shown in Fig. 9. The coupling mode $L{P_{03}}$ has an extremely small negative slope in the wavelength range of 1250-1550 nm, which is attributed to the small RI difference of the coupling modes near the GI-MMF self-imaging point. Therefore, the EULPFG is insensitive to strain, bending and RI.

 figure: Fig. 9.

Fig. 9. Calculated variation of the resonance wavelength with periods.

Download Full Size | PPT Slide | PDF

The experimental results show that the RI, strain and bending sensitivities of the EULPFG are −2.24 nm/RIU, −5.45×10−2 pm/µε and −2.25 nm/m−1, respectively. The sensitivities are one to two orders of magnitude lower than those of the same type of sensors [2224]. In terms of crosstalk, the strain-temperature cross-sensitivity of the proposed sensor is −6.00×10−4 °С/µε, which is two orders of magnitude lower than that of other LPFG sensor [25]. It indicates that the effect of strain on temperature measurement can be ignored. The cross-sensitivity of the RI and bending is −24.68 °С/RIU and −24.79 °С/m−1, which are more than 30 times smaller than that of the general LPFGs (−818.35 °С/RIU and 855.90 °С/m−1) [26,27]. When the RI and bending change by one unit, the influence on accurate measurement of temperature is huge. However, in seawater thermometry, the RI variation at a fixed depth is small (about 0.02 RIU). Therefore, the EULPFG not only inherits the advantages of optical fiber sensor [28], but also has the ability to suppress multi-parameters interference, which can achieve accurate measurement of seawater temperature.

4. Conclusion

In this paper, a high stability temperature sensor is proposed. The 700 µm GI-MMF is periodically embedded into the SMF, and the EULPFG not only shows excellent temperature sensitivity, but also has inhibition effect on other physical parameters. In addition, the resonant peak with an insertion loss of −4.33 dB and a contrast ratio of −34.62 dB ensures accurate parameter measurement through wavelength demodulation. The temperature sensitivity is 90.77 pm/°C. The advantages of easy preparation, high temperature stability and low cross-sensitivity make the sensor suitable for precise temperature measurements in the ocean.

Funding

Joint Research Fund in Astronomy under cooperative agreement between the National Natural Science Foundation of China (NSFC) and Chinese Academy of Sciences (CAS) (U1831115, U1931206, U2031130, U2031132); National Natural Science Foundation of China (11704086, 61775044); Natural Science Foundation of Heilongjiang Province (ZD2019H003); Project of Shandong Province Higher Educational Youth Innovation Science and Technology Program (2019KJJ011); Fundamental Research Funds for the Central Universities to the Harbin Engineering University.

Disclosures

The authors declare no conflicts of interest.

Data availability

Data underlying the results presented in this paper are not publicly available at this time but may be obtained from the authors upon reasonable request.

References

1. M. Lotfi and M. Noori, “A highly-sensitive temperature sensor based on GeO2–SiO2 long period fiber grating,” Phys. Scr. 96(1), 015505 (2020). [CrossRef]  

2. X. Xu, M. Luo, J. Liu, and N. Luan, “Fluorinated Polyimide-Film Based Temperature and Humidity Sensor Utilizing Fiber Bragg Grating,” Sensors 20(19), 5469 (2020). [CrossRef]  

3. J. Ma, S. Wu, H. Cheng, X. Yang, S. Wang, and P. Lu, “Sensitivity-enhanced temperature sensor based on encapsulated S-taper fiber Modal interferometer,” Opt. Laser Technol. 139, 106933 (2021). [CrossRef]  

4. N. Zhao, Q. Lin, K. Yao, F. Zhang, B. Tian, F. Chen, and Z. Jiang, “Simultaneous Measurement of Temperature and Refractive Index Using High Temperature Resistant Pure Quartz Grating Based on Femtosecond Laser and HF Etching,” Materials 14(4), 1028 (2021). [CrossRef]  

5. Y. Liu, X. Song, B. Li, J. Dong, L. Huang, D. Yu, and D. Feng, “Simultaneous measurement of temperature and strain based on SCF-based MZI cascaded with FBG,” Appl. Opt. 59(30), 9476–9481 (2020). [CrossRef]  

6. B. Pang, Z. Gu, Q. Ling, W. Wu, and Y. Zhou, “Simultaneous measurement of temperature and surrounding refractive index by superimposed coated long period fiber grating and fiber Bragg grating sensor based on mode barrier region,” Optik 220, 165136 (2020). [CrossRef]  

7. S. Zhang, S. Deng, T. Geng, C. Sun, H. Niu, X. Li, Z. Wang, X. Li, Y. Ma, W. Yang, C. Tong, and L. Yuan, “A miniature ultra long period fiber grating for simultaneous measurement of axial strain and temperature,” Opt. Laser Technol. 126, 106121 (2020). [CrossRef]  

8. S. Zhang, X. Li, H. Niu, Q. Yan, C. Sun, F. Peng, Y. Ma, K. Zhang, T. Geng, W. Yang, W. Sun, and L. Yuan, “Few-mode fiber-embedded long-period fiber grating for simultaneous measurement of refractive index and temperature,” Appl. Opt. 59(29), 9248–9253 (2020). [CrossRef]  

9. S. Yao, Y. Shen, Y. Wu, W. Jin, and S. Jian, “Strain-insensitive temperature sensor based on a few-mode dual-concentric-core fiber,” Opt. Laser Technol. 111, 95–99 (2019). [CrossRef]  

10. S. Song, A. Jung, S. Hong, and K. Oh, “Strain-Insensitive Biocompatible Temperature Sensor Based on DNA Solid Film on an Optical Microfiber,” IEEE Photonics Technol. Lett. 31(24), 1925–1928 (2019). [CrossRef]  

11. F. Beltran-Mejia, C. R. Biazoli, and C. M. Cordeiro, “Tapered GRIN fiber microsensor,” Opt. Express 22(25), 30432–30441 (2014). [CrossRef]  

12. S. Lei, C. Kin Seng, and L. Chao, “CO2-Laser-Induced Long-Period Gratings in Graded-Index Multimode Fibers for Sensor Applications,” IEEE Photonics Technol. Lett. 18(1), 190–192 (2006). [CrossRef]  

13. R. H. Fan, L. Q. Li, C. C. Wang, Y. D. Deng, X. X. Lv, Z. J. Ren, J. G. Shen, and B. J. Peng, “Interference-Type High-Sensitivity Temperature Sensor Based on the Photosensitive Fiber Microsphere,” IEEE Sens. J. 19(24), 11941–11945 (2019). [CrossRef]  

14. F. C. Favero, R. Spittel, F. Just, J. Kobelke, M. Rothhardt, and H. Bartelt, “A miniature temperature high germanium doped PCF interferometer sensor,” Opt. Express 21(25), 30266–30274 (2013). [CrossRef]  

15. C. Lu, X. Jin, S. Wang, Z. Xiang, C. Sun, X. Chen, Y. Ma, Q. Zhu, C. Tong, T. Geng, W. Sun, and L. Yuan, “High Torsion Sensitivity Sensor Based on LPFG With Unique Geometric Structure,” IEEE Sens. J. 21(5), 6217–6223 (2021). [CrossRef]  

16. Z. Liu, X. Zhao, C. Mou, and Y. Liu, “Mode Selective Conversion Enabled by the Long-Period Gratings Inscribed in Elliptical Core Few-Mode Fiber,” J. Lightwave Technol. 38(6), 1536–1542 (2020). [CrossRef]  

17. W. Liu, C. Sun, T. Geng, X. Jin, X. Chen, L. Yu, C. Zhao, X. Bai, S. Duan, H. Du, and L. Yuan, “A New Spring-Shaped Long-Period Fiber Grating With High Strain Sensitivity,” IEEE Photonics Technol. Lett. 31(14), 1163–1166 (2019). [CrossRef]  

18. X. D. Li Qiu-shun, M. Qing-jun, Y. Jun-hui, S. Jian-guo, and D. Wen-fei, “Design and test of transmission mode measurement device based on long period fiber grating with a single end face,” Chinese Opt. 10(6), 783–789 (2017). [CrossRef]  

19. S. Zhang, T. Geng, H. Niu, X. Li, Y. Yan, C. Sun, S. Deng, Z. Wang, S. Wang, W. Yang, W. Sun, and L. Yuan, “All fiber compact bending sensor with high sensitivity based on a multimode fiber embedded chirped long-period grating,” Opt. Lett. 45(15), 4172–4175 (2020). [CrossRef]  

20. X. W. Shu, L. Zhang, and I. Bennion, “Sensitivity characteristics near the dispersion turning points of long-period fiber gratings in B/Ge codoped fiber,” Opt. Lett. 26(22), 1755–1757 (2001). [CrossRef]  

21. L. Z. Xuewen Shu, O. S. A. Member, and I. Bennion, “Sensing Characteristics of Long-Period Fiber Grating,” J. Lightwave Technol. 20(2), 255–266 (2002). [CrossRef]  

22. H. I. Stawska and M. A. Popenda, “Refractive Index Sensors Based on Long-Period Grating in a Negative Curvature Hollow-Core Fiber,” Sensors 21(5), 1803 (2021). [CrossRef]  

23. S. S. Zhang, C. Q. Fang, C. Zhang, J. Shi, J. F. Zhao, Y. G. Liu, E. D. Gu, and J. Q. Yao, “A Compact Ultra-Long Period Fiber Grating Based on Cascading Up-Tapers,” IEEE Sens. J. 20, 8552–8558 (2020). [CrossRef]  

24. T. E. Porraz-Culebro, A. Martinez-Rios, D. Toral-Acosta, K. Madrazo-de-la-Rosa, L. F. Enriquez-Gomez, J. M. Sierra-Hernandez, and G. Salceda-Delgado, “Characteristics of LPFGs Written by a CO2-Laser Glass Processing System,” J. Lightwave Technol. 37(4), 1301–1309 (2019). [CrossRef]  

25. X. Cao, D. Tian, Y. Liu, L. Zhang, and T. Wang, “Sensing Characteristics of Helical Long-Period Gratings Written in the Double-Clad Fiber by CO2 Laser,” IEEE Sens. J. 18(18), 7481–7485 (2018). [CrossRef]  

26. M. Luo and Q. Wang, “Fabrication and sensing characteristics of arc-induced long-period fiber gratings based on thin-cladding fiber,” Alexandria Eng. J. 59(5), 3681–3686 (2020). [CrossRef]  

27. S. J. Jeong, J. Kim, S. Choi, S. L. Lee, M. S. Kim, D. K. Kim, and Y. W. Lee, “Simultaneous Measurement of Bending and Temperature Using Long-Period Fiber Grating Inscribed on Polarization-Maintaining Fiber with CO2 Laser,” J. Nanosci. Nanotechnol. 20(1), 285–292 (2020). [CrossRef]  

28. J. Zhao, H. Wang, and X. Sun, “Study on the performance of polarization maintaining fiber temperature sensor based on tilted fiber grating,” Measurement 168, 108421 (2021). [CrossRef]  

References

  • View by:

  1. M. Lotfi and M. Noori, “A highly-sensitive temperature sensor based on GeO2–SiO2 long period fiber grating,” Phys. Scr. 96(1), 015505 (2020).
    [Crossref]
  2. X. Xu, M. Luo, J. Liu, and N. Luan, “Fluorinated Polyimide-Film Based Temperature and Humidity Sensor Utilizing Fiber Bragg Grating,” Sensors 20(19), 5469 (2020).
    [Crossref]
  3. J. Ma, S. Wu, H. Cheng, X. Yang, S. Wang, and P. Lu, “Sensitivity-enhanced temperature sensor based on encapsulated S-taper fiber Modal interferometer,” Opt. Laser Technol. 139, 106933 (2021).
    [Crossref]
  4. N. Zhao, Q. Lin, K. Yao, F. Zhang, B. Tian, F. Chen, and Z. Jiang, “Simultaneous Measurement of Temperature and Refractive Index Using High Temperature Resistant Pure Quartz Grating Based on Femtosecond Laser and HF Etching,” Materials 14(4), 1028 (2021).
    [Crossref]
  5. Y. Liu, X. Song, B. Li, J. Dong, L. Huang, D. Yu, and D. Feng, “Simultaneous measurement of temperature and strain based on SCF-based MZI cascaded with FBG,” Appl. Opt. 59(30), 9476–9481 (2020).
    [Crossref]
  6. B. Pang, Z. Gu, Q. Ling, W. Wu, and Y. Zhou, “Simultaneous measurement of temperature and surrounding refractive index by superimposed coated long period fiber grating and fiber Bragg grating sensor based on mode barrier region,” Optik 220, 165136 (2020).
    [Crossref]
  7. S. Zhang, S. Deng, T. Geng, C. Sun, H. Niu, X. Li, Z. Wang, X. Li, Y. Ma, W. Yang, C. Tong, and L. Yuan, “A miniature ultra long period fiber grating for simultaneous measurement of axial strain and temperature,” Opt. Laser Technol. 126, 106121 (2020).
    [Crossref]
  8. S. Zhang, X. Li, H. Niu, Q. Yan, C. Sun, F. Peng, Y. Ma, K. Zhang, T. Geng, W. Yang, W. Sun, and L. Yuan, “Few-mode fiber-embedded long-period fiber grating for simultaneous measurement of refractive index and temperature,” Appl. Opt. 59(29), 9248–9253 (2020).
    [Crossref]
  9. S. Yao, Y. Shen, Y. Wu, W. Jin, and S. Jian, “Strain-insensitive temperature sensor based on a few-mode dual-concentric-core fiber,” Opt. Laser Technol. 111, 95–99 (2019).
    [Crossref]
  10. S. Song, A. Jung, S. Hong, and K. Oh, “Strain-Insensitive Biocompatible Temperature Sensor Based on DNA Solid Film on an Optical Microfiber,” IEEE Photonics Technol. Lett. 31(24), 1925–1928 (2019).
    [Crossref]
  11. F. Beltran-Mejia, C. R. Biazoli, and C. M. Cordeiro, “Tapered GRIN fiber microsensor,” Opt. Express 22(25), 30432–30441 (2014).
    [Crossref]
  12. S. Lei, C. Kin Seng, and L. Chao, “CO2-Laser-Induced Long-Period Gratings in Graded-Index Multimode Fibers for Sensor Applications,” IEEE Photonics Technol. Lett. 18(1), 190–192 (2006).
    [Crossref]
  13. R. H. Fan, L. Q. Li, C. C. Wang, Y. D. Deng, X. X. Lv, Z. J. Ren, J. G. Shen, and B. J. Peng, “Interference-Type High-Sensitivity Temperature Sensor Based on the Photosensitive Fiber Microsphere,” IEEE Sens. J. 19(24), 11941–11945 (2019).
    [Crossref]
  14. F. C. Favero, R. Spittel, F. Just, J. Kobelke, M. Rothhardt, and H. Bartelt, “A miniature temperature high germanium doped PCF interferometer sensor,” Opt. Express 21(25), 30266–30274 (2013).
    [Crossref]
  15. C. Lu, X. Jin, S. Wang, Z. Xiang, C. Sun, X. Chen, Y. Ma, Q. Zhu, C. Tong, T. Geng, W. Sun, and L. Yuan, “High Torsion Sensitivity Sensor Based on LPFG With Unique Geometric Structure,” IEEE Sens. J. 21(5), 6217–6223 (2021).
    [Crossref]
  16. Z. Liu, X. Zhao, C. Mou, and Y. Liu, “Mode Selective Conversion Enabled by the Long-Period Gratings Inscribed in Elliptical Core Few-Mode Fiber,” J. Lightwave Technol. 38(6), 1536–1542 (2020).
    [Crossref]
  17. W. Liu, C. Sun, T. Geng, X. Jin, X. Chen, L. Yu, C. Zhao, X. Bai, S. Duan, H. Du, and L. Yuan, “A New Spring-Shaped Long-Period Fiber Grating With High Strain Sensitivity,” IEEE Photonics Technol. Lett. 31(14), 1163–1166 (2019).
    [Crossref]
  18. X. D. Li Qiu-shun, M. Qing-jun, Y. Jun-hui, S. Jian-guo, and D. Wen-fei, “Design and test of transmission mode measurement device based on long period fiber grating with a single end face,” Chinese Opt. 10(6), 783–789 (2017).
    [Crossref]
  19. S. Zhang, T. Geng, H. Niu, X. Li, Y. Yan, C. Sun, S. Deng, Z. Wang, S. Wang, W. Yang, W. Sun, and L. Yuan, “All fiber compact bending sensor with high sensitivity based on a multimode fiber embedded chirped long-period grating,” Opt. Lett. 45(15), 4172–4175 (2020).
    [Crossref]
  20. X. W. Shu, L. Zhang, and I. Bennion, “Sensitivity characteristics near the dispersion turning points of long-period fiber gratings in B/Ge codoped fiber,” Opt. Lett. 26(22), 1755–1757 (2001).
    [Crossref]
  21. L. Z. Xuewen Shu, O. S. A. Member, and I. Bennion, “Sensing Characteristics of Long-Period Fiber Grating,” J. Lightwave Technol. 20(2), 255–266 (2002).
    [Crossref]
  22. H. I. Stawska and M. A. Popenda, “Refractive Index Sensors Based on Long-Period Grating in a Negative Curvature Hollow-Core Fiber,” Sensors 21(5), 1803 (2021).
    [Crossref]
  23. S. S. Zhang, C. Q. Fang, C. Zhang, J. Shi, J. F. Zhao, Y. G. Liu, E. D. Gu, and J. Q. Yao, “A Compact Ultra-Long Period Fiber Grating Based on Cascading Up-Tapers,” IEEE Sens. J. 20, 8552–8558 (2020).
    [Crossref]
  24. T. E. Porraz-Culebro, A. Martinez-Rios, D. Toral-Acosta, K. Madrazo-de-la-Rosa, L. F. Enriquez-Gomez, J. M. Sierra-Hernandez, and G. Salceda-Delgado, “Characteristics of LPFGs Written by a CO2-Laser Glass Processing System,” J. Lightwave Technol. 37(4), 1301–1309 (2019).
    [Crossref]
  25. X. Cao, D. Tian, Y. Liu, L. Zhang, and T. Wang, “Sensing Characteristics of Helical Long-Period Gratings Written in the Double-Clad Fiber by CO2 Laser,” IEEE Sens. J. 18(18), 7481–7485 (2018).
    [Crossref]
  26. M. Luo and Q. Wang, “Fabrication and sensing characteristics of arc-induced long-period fiber gratings based on thin-cladding fiber,” Alexandria Eng. J. 59(5), 3681–3686 (2020).
    [Crossref]
  27. S. J. Jeong, J. Kim, S. Choi, S. L. Lee, M. S. Kim, D. K. Kim, and Y. W. Lee, “Simultaneous Measurement of Bending and Temperature Using Long-Period Fiber Grating Inscribed on Polarization-Maintaining Fiber with CO2 Laser,” J. Nanosci. Nanotechnol. 20(1), 285–292 (2020).
    [Crossref]
  28. J. Zhao, H. Wang, and X. Sun, “Study on the performance of polarization maintaining fiber temperature sensor based on tilted fiber grating,” Measurement 168, 108421 (2021).
    [Crossref]

2021 (5)

J. Ma, S. Wu, H. Cheng, X. Yang, S. Wang, and P. Lu, “Sensitivity-enhanced temperature sensor based on encapsulated S-taper fiber Modal interferometer,” Opt. Laser Technol. 139, 106933 (2021).
[Crossref]

N. Zhao, Q. Lin, K. Yao, F. Zhang, B. Tian, F. Chen, and Z. Jiang, “Simultaneous Measurement of Temperature and Refractive Index Using High Temperature Resistant Pure Quartz Grating Based on Femtosecond Laser and HF Etching,” Materials 14(4), 1028 (2021).
[Crossref]

C. Lu, X. Jin, S. Wang, Z. Xiang, C. Sun, X. Chen, Y. Ma, Q. Zhu, C. Tong, T. Geng, W. Sun, and L. Yuan, “High Torsion Sensitivity Sensor Based on LPFG With Unique Geometric Structure,” IEEE Sens. J. 21(5), 6217–6223 (2021).
[Crossref]

H. I. Stawska and M. A. Popenda, “Refractive Index Sensors Based on Long-Period Grating in a Negative Curvature Hollow-Core Fiber,” Sensors 21(5), 1803 (2021).
[Crossref]

J. Zhao, H. Wang, and X. Sun, “Study on the performance of polarization maintaining fiber temperature sensor based on tilted fiber grating,” Measurement 168, 108421 (2021).
[Crossref]

2020 (11)

S. S. Zhang, C. Q. Fang, C. Zhang, J. Shi, J. F. Zhao, Y. G. Liu, E. D. Gu, and J. Q. Yao, “A Compact Ultra-Long Period Fiber Grating Based on Cascading Up-Tapers,” IEEE Sens. J. 20, 8552–8558 (2020).
[Crossref]

S. Zhang, T. Geng, H. Niu, X. Li, Y. Yan, C. Sun, S. Deng, Z. Wang, S. Wang, W. Yang, W. Sun, and L. Yuan, “All fiber compact bending sensor with high sensitivity based on a multimode fiber embedded chirped long-period grating,” Opt. Lett. 45(15), 4172–4175 (2020).
[Crossref]

M. Luo and Q. Wang, “Fabrication and sensing characteristics of arc-induced long-period fiber gratings based on thin-cladding fiber,” Alexandria Eng. J. 59(5), 3681–3686 (2020).
[Crossref]

S. J. Jeong, J. Kim, S. Choi, S. L. Lee, M. S. Kim, D. K. Kim, and Y. W. Lee, “Simultaneous Measurement of Bending and Temperature Using Long-Period Fiber Grating Inscribed on Polarization-Maintaining Fiber with CO2 Laser,” J. Nanosci. Nanotechnol. 20(1), 285–292 (2020).
[Crossref]

Z. Liu, X. Zhao, C. Mou, and Y. Liu, “Mode Selective Conversion Enabled by the Long-Period Gratings Inscribed in Elliptical Core Few-Mode Fiber,” J. Lightwave Technol. 38(6), 1536–1542 (2020).
[Crossref]

M. Lotfi and M. Noori, “A highly-sensitive temperature sensor based on GeO2–SiO2 long period fiber grating,” Phys. Scr. 96(1), 015505 (2020).
[Crossref]

X. Xu, M. Luo, J. Liu, and N. Luan, “Fluorinated Polyimide-Film Based Temperature and Humidity Sensor Utilizing Fiber Bragg Grating,” Sensors 20(19), 5469 (2020).
[Crossref]

Y. Liu, X. Song, B. Li, J. Dong, L. Huang, D. Yu, and D. Feng, “Simultaneous measurement of temperature and strain based on SCF-based MZI cascaded with FBG,” Appl. Opt. 59(30), 9476–9481 (2020).
[Crossref]

B. Pang, Z. Gu, Q. Ling, W. Wu, and Y. Zhou, “Simultaneous measurement of temperature and surrounding refractive index by superimposed coated long period fiber grating and fiber Bragg grating sensor based on mode barrier region,” Optik 220, 165136 (2020).
[Crossref]

S. Zhang, S. Deng, T. Geng, C. Sun, H. Niu, X. Li, Z. Wang, X. Li, Y. Ma, W. Yang, C. Tong, and L. Yuan, “A miniature ultra long period fiber grating for simultaneous measurement of axial strain and temperature,” Opt. Laser Technol. 126, 106121 (2020).
[Crossref]

S. Zhang, X. Li, H. Niu, Q. Yan, C. Sun, F. Peng, Y. Ma, K. Zhang, T. Geng, W. Yang, W. Sun, and L. Yuan, “Few-mode fiber-embedded long-period fiber grating for simultaneous measurement of refractive index and temperature,” Appl. Opt. 59(29), 9248–9253 (2020).
[Crossref]

2019 (5)

S. Yao, Y. Shen, Y. Wu, W. Jin, and S. Jian, “Strain-insensitive temperature sensor based on a few-mode dual-concentric-core fiber,” Opt. Laser Technol. 111, 95–99 (2019).
[Crossref]

S. Song, A. Jung, S. Hong, and K. Oh, “Strain-Insensitive Biocompatible Temperature Sensor Based on DNA Solid Film on an Optical Microfiber,” IEEE Photonics Technol. Lett. 31(24), 1925–1928 (2019).
[Crossref]

R. H. Fan, L. Q. Li, C. C. Wang, Y. D. Deng, X. X. Lv, Z. J. Ren, J. G. Shen, and B. J. Peng, “Interference-Type High-Sensitivity Temperature Sensor Based on the Photosensitive Fiber Microsphere,” IEEE Sens. J. 19(24), 11941–11945 (2019).
[Crossref]

W. Liu, C. Sun, T. Geng, X. Jin, X. Chen, L. Yu, C. Zhao, X. Bai, S. Duan, H. Du, and L. Yuan, “A New Spring-Shaped Long-Period Fiber Grating With High Strain Sensitivity,” IEEE Photonics Technol. Lett. 31(14), 1163–1166 (2019).
[Crossref]

T. E. Porraz-Culebro, A. Martinez-Rios, D. Toral-Acosta, K. Madrazo-de-la-Rosa, L. F. Enriquez-Gomez, J. M. Sierra-Hernandez, and G. Salceda-Delgado, “Characteristics of LPFGs Written by a CO2-Laser Glass Processing System,” J. Lightwave Technol. 37(4), 1301–1309 (2019).
[Crossref]

2018 (1)

X. Cao, D. Tian, Y. Liu, L. Zhang, and T. Wang, “Sensing Characteristics of Helical Long-Period Gratings Written in the Double-Clad Fiber by CO2 Laser,” IEEE Sens. J. 18(18), 7481–7485 (2018).
[Crossref]

2017 (1)

X. D. Li Qiu-shun, M. Qing-jun, Y. Jun-hui, S. Jian-guo, and D. Wen-fei, “Design and test of transmission mode measurement device based on long period fiber grating with a single end face,” Chinese Opt. 10(6), 783–789 (2017).
[Crossref]

2014 (1)

2013 (1)

2006 (1)

S. Lei, C. Kin Seng, and L. Chao, “CO2-Laser-Induced Long-Period Gratings in Graded-Index Multimode Fibers for Sensor Applications,” IEEE Photonics Technol. Lett. 18(1), 190–192 (2006).
[Crossref]

2002 (1)

2001 (1)

Bai, X.

W. Liu, C. Sun, T. Geng, X. Jin, X. Chen, L. Yu, C. Zhao, X. Bai, S. Duan, H. Du, and L. Yuan, “A New Spring-Shaped Long-Period Fiber Grating With High Strain Sensitivity,” IEEE Photonics Technol. Lett. 31(14), 1163–1166 (2019).
[Crossref]

Bartelt, H.

Beltran-Mejia, F.

Bennion, I.

Biazoli, C. R.

Cao, X.

X. Cao, D. Tian, Y. Liu, L. Zhang, and T. Wang, “Sensing Characteristics of Helical Long-Period Gratings Written in the Double-Clad Fiber by CO2 Laser,” IEEE Sens. J. 18(18), 7481–7485 (2018).
[Crossref]

Chao, L.

S. Lei, C. Kin Seng, and L. Chao, “CO2-Laser-Induced Long-Period Gratings in Graded-Index Multimode Fibers for Sensor Applications,” IEEE Photonics Technol. Lett. 18(1), 190–192 (2006).
[Crossref]

Chen, F.

N. Zhao, Q. Lin, K. Yao, F. Zhang, B. Tian, F. Chen, and Z. Jiang, “Simultaneous Measurement of Temperature and Refractive Index Using High Temperature Resistant Pure Quartz Grating Based on Femtosecond Laser and HF Etching,” Materials 14(4), 1028 (2021).
[Crossref]

Chen, X.

C. Lu, X. Jin, S. Wang, Z. Xiang, C. Sun, X. Chen, Y. Ma, Q. Zhu, C. Tong, T. Geng, W. Sun, and L. Yuan, “High Torsion Sensitivity Sensor Based on LPFG With Unique Geometric Structure,” IEEE Sens. J. 21(5), 6217–6223 (2021).
[Crossref]

W. Liu, C. Sun, T. Geng, X. Jin, X. Chen, L. Yu, C. Zhao, X. Bai, S. Duan, H. Du, and L. Yuan, “A New Spring-Shaped Long-Period Fiber Grating With High Strain Sensitivity,” IEEE Photonics Technol. Lett. 31(14), 1163–1166 (2019).
[Crossref]

Cheng, H.

J. Ma, S. Wu, H. Cheng, X. Yang, S. Wang, and P. Lu, “Sensitivity-enhanced temperature sensor based on encapsulated S-taper fiber Modal interferometer,” Opt. Laser Technol. 139, 106933 (2021).
[Crossref]

Choi, S.

S. J. Jeong, J. Kim, S. Choi, S. L. Lee, M. S. Kim, D. K. Kim, and Y. W. Lee, “Simultaneous Measurement of Bending and Temperature Using Long-Period Fiber Grating Inscribed on Polarization-Maintaining Fiber with CO2 Laser,” J. Nanosci. Nanotechnol. 20(1), 285–292 (2020).
[Crossref]

Cordeiro, C. M.

Deng, S.

S. Zhang, S. Deng, T. Geng, C. Sun, H. Niu, X. Li, Z. Wang, X. Li, Y. Ma, W. Yang, C. Tong, and L. Yuan, “A miniature ultra long period fiber grating for simultaneous measurement of axial strain and temperature,” Opt. Laser Technol. 126, 106121 (2020).
[Crossref]

S. Zhang, T. Geng, H. Niu, X. Li, Y. Yan, C. Sun, S. Deng, Z. Wang, S. Wang, W. Yang, W. Sun, and L. Yuan, “All fiber compact bending sensor with high sensitivity based on a multimode fiber embedded chirped long-period grating,” Opt. Lett. 45(15), 4172–4175 (2020).
[Crossref]

Deng, Y. D.

R. H. Fan, L. Q. Li, C. C. Wang, Y. D. Deng, X. X. Lv, Z. J. Ren, J. G. Shen, and B. J. Peng, “Interference-Type High-Sensitivity Temperature Sensor Based on the Photosensitive Fiber Microsphere,” IEEE Sens. J. 19(24), 11941–11945 (2019).
[Crossref]

Dong, J.

Du, H.

W. Liu, C. Sun, T. Geng, X. Jin, X. Chen, L. Yu, C. Zhao, X. Bai, S. Duan, H. Du, and L. Yuan, “A New Spring-Shaped Long-Period Fiber Grating With High Strain Sensitivity,” IEEE Photonics Technol. Lett. 31(14), 1163–1166 (2019).
[Crossref]

Duan, S.

W. Liu, C. Sun, T. Geng, X. Jin, X. Chen, L. Yu, C. Zhao, X. Bai, S. Duan, H. Du, and L. Yuan, “A New Spring-Shaped Long-Period Fiber Grating With High Strain Sensitivity,” IEEE Photonics Technol. Lett. 31(14), 1163–1166 (2019).
[Crossref]

Enriquez-Gomez, L. F.

Fan, R. H.

R. H. Fan, L. Q. Li, C. C. Wang, Y. D. Deng, X. X. Lv, Z. J. Ren, J. G. Shen, and B. J. Peng, “Interference-Type High-Sensitivity Temperature Sensor Based on the Photosensitive Fiber Microsphere,” IEEE Sens. J. 19(24), 11941–11945 (2019).
[Crossref]

Fang, C. Q.

S. S. Zhang, C. Q. Fang, C. Zhang, J. Shi, J. F. Zhao, Y. G. Liu, E. D. Gu, and J. Q. Yao, “A Compact Ultra-Long Period Fiber Grating Based on Cascading Up-Tapers,” IEEE Sens. J. 20, 8552–8558 (2020).
[Crossref]

Favero, F. C.

Feng, D.

Geng, T.

C. Lu, X. Jin, S. Wang, Z. Xiang, C. Sun, X. Chen, Y. Ma, Q. Zhu, C. Tong, T. Geng, W. Sun, and L. Yuan, “High Torsion Sensitivity Sensor Based on LPFG With Unique Geometric Structure,” IEEE Sens. J. 21(5), 6217–6223 (2021).
[Crossref]

S. Zhang, T. Geng, H. Niu, X. Li, Y. Yan, C. Sun, S. Deng, Z. Wang, S. Wang, W. Yang, W. Sun, and L. Yuan, “All fiber compact bending sensor with high sensitivity based on a multimode fiber embedded chirped long-period grating,” Opt. Lett. 45(15), 4172–4175 (2020).
[Crossref]

S. Zhang, S. Deng, T. Geng, C. Sun, H. Niu, X. Li, Z. Wang, X. Li, Y. Ma, W. Yang, C. Tong, and L. Yuan, “A miniature ultra long period fiber grating for simultaneous measurement of axial strain and temperature,” Opt. Laser Technol. 126, 106121 (2020).
[Crossref]

S. Zhang, X. Li, H. Niu, Q. Yan, C. Sun, F. Peng, Y. Ma, K. Zhang, T. Geng, W. Yang, W. Sun, and L. Yuan, “Few-mode fiber-embedded long-period fiber grating for simultaneous measurement of refractive index and temperature,” Appl. Opt. 59(29), 9248–9253 (2020).
[Crossref]

W. Liu, C. Sun, T. Geng, X. Jin, X. Chen, L. Yu, C. Zhao, X. Bai, S. Duan, H. Du, and L. Yuan, “A New Spring-Shaped Long-Period Fiber Grating With High Strain Sensitivity,” IEEE Photonics Technol. Lett. 31(14), 1163–1166 (2019).
[Crossref]

Gu, E. D.

S. S. Zhang, C. Q. Fang, C. Zhang, J. Shi, J. F. Zhao, Y. G. Liu, E. D. Gu, and J. Q. Yao, “A Compact Ultra-Long Period Fiber Grating Based on Cascading Up-Tapers,” IEEE Sens. J. 20, 8552–8558 (2020).
[Crossref]

Gu, Z.

B. Pang, Z. Gu, Q. Ling, W. Wu, and Y. Zhou, “Simultaneous measurement of temperature and surrounding refractive index by superimposed coated long period fiber grating and fiber Bragg grating sensor based on mode barrier region,” Optik 220, 165136 (2020).
[Crossref]

Hong, S.

S. Song, A. Jung, S. Hong, and K. Oh, “Strain-Insensitive Biocompatible Temperature Sensor Based on DNA Solid Film on an Optical Microfiber,” IEEE Photonics Technol. Lett. 31(24), 1925–1928 (2019).
[Crossref]

Huang, L.

Jeong, S. J.

S. J. Jeong, J. Kim, S. Choi, S. L. Lee, M. S. Kim, D. K. Kim, and Y. W. Lee, “Simultaneous Measurement of Bending and Temperature Using Long-Period Fiber Grating Inscribed on Polarization-Maintaining Fiber with CO2 Laser,” J. Nanosci. Nanotechnol. 20(1), 285–292 (2020).
[Crossref]

Jian, S.

S. Yao, Y. Shen, Y. Wu, W. Jin, and S. Jian, “Strain-insensitive temperature sensor based on a few-mode dual-concentric-core fiber,” Opt. Laser Technol. 111, 95–99 (2019).
[Crossref]

Jiang, Z.

N. Zhao, Q. Lin, K. Yao, F. Zhang, B. Tian, F. Chen, and Z. Jiang, “Simultaneous Measurement of Temperature and Refractive Index Using High Temperature Resistant Pure Quartz Grating Based on Femtosecond Laser and HF Etching,” Materials 14(4), 1028 (2021).
[Crossref]

Jian-guo, S.

X. D. Li Qiu-shun, M. Qing-jun, Y. Jun-hui, S. Jian-guo, and D. Wen-fei, “Design and test of transmission mode measurement device based on long period fiber grating with a single end face,” Chinese Opt. 10(6), 783–789 (2017).
[Crossref]

Jin, W.

S. Yao, Y. Shen, Y. Wu, W. Jin, and S. Jian, “Strain-insensitive temperature sensor based on a few-mode dual-concentric-core fiber,” Opt. Laser Technol. 111, 95–99 (2019).
[Crossref]

Jin, X.

C. Lu, X. Jin, S. Wang, Z. Xiang, C. Sun, X. Chen, Y. Ma, Q. Zhu, C. Tong, T. Geng, W. Sun, and L. Yuan, “High Torsion Sensitivity Sensor Based on LPFG With Unique Geometric Structure,” IEEE Sens. J. 21(5), 6217–6223 (2021).
[Crossref]

W. Liu, C. Sun, T. Geng, X. Jin, X. Chen, L. Yu, C. Zhao, X. Bai, S. Duan, H. Du, and L. Yuan, “A New Spring-Shaped Long-Period Fiber Grating With High Strain Sensitivity,” IEEE Photonics Technol. Lett. 31(14), 1163–1166 (2019).
[Crossref]

Jung, A.

S. Song, A. Jung, S. Hong, and K. Oh, “Strain-Insensitive Biocompatible Temperature Sensor Based on DNA Solid Film on an Optical Microfiber,” IEEE Photonics Technol. Lett. 31(24), 1925–1928 (2019).
[Crossref]

Jun-hui, Y.

X. D. Li Qiu-shun, M. Qing-jun, Y. Jun-hui, S. Jian-guo, and D. Wen-fei, “Design and test of transmission mode measurement device based on long period fiber grating with a single end face,” Chinese Opt. 10(6), 783–789 (2017).
[Crossref]

Just, F.

Kim, D. K.

S. J. Jeong, J. Kim, S. Choi, S. L. Lee, M. S. Kim, D. K. Kim, and Y. W. Lee, “Simultaneous Measurement of Bending and Temperature Using Long-Period Fiber Grating Inscribed on Polarization-Maintaining Fiber with CO2 Laser,” J. Nanosci. Nanotechnol. 20(1), 285–292 (2020).
[Crossref]

Kim, J.

S. J. Jeong, J. Kim, S. Choi, S. L. Lee, M. S. Kim, D. K. Kim, and Y. W. Lee, “Simultaneous Measurement of Bending and Temperature Using Long-Period Fiber Grating Inscribed on Polarization-Maintaining Fiber with CO2 Laser,” J. Nanosci. Nanotechnol. 20(1), 285–292 (2020).
[Crossref]

Kim, M. S.

S. J. Jeong, J. Kim, S. Choi, S. L. Lee, M. S. Kim, D. K. Kim, and Y. W. Lee, “Simultaneous Measurement of Bending and Temperature Using Long-Period Fiber Grating Inscribed on Polarization-Maintaining Fiber with CO2 Laser,” J. Nanosci. Nanotechnol. 20(1), 285–292 (2020).
[Crossref]

Kin Seng, C.

S. Lei, C. Kin Seng, and L. Chao, “CO2-Laser-Induced Long-Period Gratings in Graded-Index Multimode Fibers for Sensor Applications,” IEEE Photonics Technol. Lett. 18(1), 190–192 (2006).
[Crossref]

Kobelke, J.

Lee, S. L.

S. J. Jeong, J. Kim, S. Choi, S. L. Lee, M. S. Kim, D. K. Kim, and Y. W. Lee, “Simultaneous Measurement of Bending and Temperature Using Long-Period Fiber Grating Inscribed on Polarization-Maintaining Fiber with CO2 Laser,” J. Nanosci. Nanotechnol. 20(1), 285–292 (2020).
[Crossref]

Lee, Y. W.

S. J. Jeong, J. Kim, S. Choi, S. L. Lee, M. S. Kim, D. K. Kim, and Y. W. Lee, “Simultaneous Measurement of Bending and Temperature Using Long-Period Fiber Grating Inscribed on Polarization-Maintaining Fiber with CO2 Laser,” J. Nanosci. Nanotechnol. 20(1), 285–292 (2020).
[Crossref]

Lei, S.

S. Lei, C. Kin Seng, and L. Chao, “CO2-Laser-Induced Long-Period Gratings in Graded-Index Multimode Fibers for Sensor Applications,” IEEE Photonics Technol. Lett. 18(1), 190–192 (2006).
[Crossref]

Li, B.

Li, L. Q.

R. H. Fan, L. Q. Li, C. C. Wang, Y. D. Deng, X. X. Lv, Z. J. Ren, J. G. Shen, and B. J. Peng, “Interference-Type High-Sensitivity Temperature Sensor Based on the Photosensitive Fiber Microsphere,” IEEE Sens. J. 19(24), 11941–11945 (2019).
[Crossref]

Li, X.

S. Zhang, S. Deng, T. Geng, C. Sun, H. Niu, X. Li, Z. Wang, X. Li, Y. Ma, W. Yang, C. Tong, and L. Yuan, “A miniature ultra long period fiber grating for simultaneous measurement of axial strain and temperature,” Opt. Laser Technol. 126, 106121 (2020).
[Crossref]

S. Zhang, S. Deng, T. Geng, C. Sun, H. Niu, X. Li, Z. Wang, X. Li, Y. Ma, W. Yang, C. Tong, and L. Yuan, “A miniature ultra long period fiber grating for simultaneous measurement of axial strain and temperature,” Opt. Laser Technol. 126, 106121 (2020).
[Crossref]

S. Zhang, X. Li, H. Niu, Q. Yan, C. Sun, F. Peng, Y. Ma, K. Zhang, T. Geng, W. Yang, W. Sun, and L. Yuan, “Few-mode fiber-embedded long-period fiber grating for simultaneous measurement of refractive index and temperature,” Appl. Opt. 59(29), 9248–9253 (2020).
[Crossref]

S. Zhang, T. Geng, H. Niu, X. Li, Y. Yan, C. Sun, S. Deng, Z. Wang, S. Wang, W. Yang, W. Sun, and L. Yuan, “All fiber compact bending sensor with high sensitivity based on a multimode fiber embedded chirped long-period grating,” Opt. Lett. 45(15), 4172–4175 (2020).
[Crossref]

Li Qiu-shun, X. D.

X. D. Li Qiu-shun, M. Qing-jun, Y. Jun-hui, S. Jian-guo, and D. Wen-fei, “Design and test of transmission mode measurement device based on long period fiber grating with a single end face,” Chinese Opt. 10(6), 783–789 (2017).
[Crossref]

Lin, Q.

N. Zhao, Q. Lin, K. Yao, F. Zhang, B. Tian, F. Chen, and Z. Jiang, “Simultaneous Measurement of Temperature and Refractive Index Using High Temperature Resistant Pure Quartz Grating Based on Femtosecond Laser and HF Etching,” Materials 14(4), 1028 (2021).
[Crossref]

Ling, Q.

B. Pang, Z. Gu, Q. Ling, W. Wu, and Y. Zhou, “Simultaneous measurement of temperature and surrounding refractive index by superimposed coated long period fiber grating and fiber Bragg grating sensor based on mode barrier region,” Optik 220, 165136 (2020).
[Crossref]

Liu, J.

X. Xu, M. Luo, J. Liu, and N. Luan, “Fluorinated Polyimide-Film Based Temperature and Humidity Sensor Utilizing Fiber Bragg Grating,” Sensors 20(19), 5469 (2020).
[Crossref]

Liu, W.

W. Liu, C. Sun, T. Geng, X. Jin, X. Chen, L. Yu, C. Zhao, X. Bai, S. Duan, H. Du, and L. Yuan, “A New Spring-Shaped Long-Period Fiber Grating With High Strain Sensitivity,” IEEE Photonics Technol. Lett. 31(14), 1163–1166 (2019).
[Crossref]

Liu, Y.

Liu, Y. G.

S. S. Zhang, C. Q. Fang, C. Zhang, J. Shi, J. F. Zhao, Y. G. Liu, E. D. Gu, and J. Q. Yao, “A Compact Ultra-Long Period Fiber Grating Based on Cascading Up-Tapers,” IEEE Sens. J. 20, 8552–8558 (2020).
[Crossref]

Liu, Z.

Lotfi, M.

M. Lotfi and M. Noori, “A highly-sensitive temperature sensor based on GeO2–SiO2 long period fiber grating,” Phys. Scr. 96(1), 015505 (2020).
[Crossref]

Lu, C.

C. Lu, X. Jin, S. Wang, Z. Xiang, C. Sun, X. Chen, Y. Ma, Q. Zhu, C. Tong, T. Geng, W. Sun, and L. Yuan, “High Torsion Sensitivity Sensor Based on LPFG With Unique Geometric Structure,” IEEE Sens. J. 21(5), 6217–6223 (2021).
[Crossref]

Lu, P.

J. Ma, S. Wu, H. Cheng, X. Yang, S. Wang, and P. Lu, “Sensitivity-enhanced temperature sensor based on encapsulated S-taper fiber Modal interferometer,” Opt. Laser Technol. 139, 106933 (2021).
[Crossref]

Luan, N.

X. Xu, M. Luo, J. Liu, and N. Luan, “Fluorinated Polyimide-Film Based Temperature and Humidity Sensor Utilizing Fiber Bragg Grating,” Sensors 20(19), 5469 (2020).
[Crossref]

Luo, M.

X. Xu, M. Luo, J. Liu, and N. Luan, “Fluorinated Polyimide-Film Based Temperature and Humidity Sensor Utilizing Fiber Bragg Grating,” Sensors 20(19), 5469 (2020).
[Crossref]

M. Luo and Q. Wang, “Fabrication and sensing characteristics of arc-induced long-period fiber gratings based on thin-cladding fiber,” Alexandria Eng. J. 59(5), 3681–3686 (2020).
[Crossref]

Lv, X. X.

R. H. Fan, L. Q. Li, C. C. Wang, Y. D. Deng, X. X. Lv, Z. J. Ren, J. G. Shen, and B. J. Peng, “Interference-Type High-Sensitivity Temperature Sensor Based on the Photosensitive Fiber Microsphere,” IEEE Sens. J. 19(24), 11941–11945 (2019).
[Crossref]

Ma, J.

J. Ma, S. Wu, H. Cheng, X. Yang, S. Wang, and P. Lu, “Sensitivity-enhanced temperature sensor based on encapsulated S-taper fiber Modal interferometer,” Opt. Laser Technol. 139, 106933 (2021).
[Crossref]

Ma, Y.

C. Lu, X. Jin, S. Wang, Z. Xiang, C. Sun, X. Chen, Y. Ma, Q. Zhu, C. Tong, T. Geng, W. Sun, and L. Yuan, “High Torsion Sensitivity Sensor Based on LPFG With Unique Geometric Structure,” IEEE Sens. J. 21(5), 6217–6223 (2021).
[Crossref]

S. Zhang, S. Deng, T. Geng, C. Sun, H. Niu, X. Li, Z. Wang, X. Li, Y. Ma, W. Yang, C. Tong, and L. Yuan, “A miniature ultra long period fiber grating for simultaneous measurement of axial strain and temperature,” Opt. Laser Technol. 126, 106121 (2020).
[Crossref]

S. Zhang, X. Li, H. Niu, Q. Yan, C. Sun, F. Peng, Y. Ma, K. Zhang, T. Geng, W. Yang, W. Sun, and L. Yuan, “Few-mode fiber-embedded long-period fiber grating for simultaneous measurement of refractive index and temperature,” Appl. Opt. 59(29), 9248–9253 (2020).
[Crossref]

Madrazo-de-la-Rosa, K.

Martinez-Rios, A.

Member, O. S. A.

Mou, C.

Niu, H.

Noori, M.

M. Lotfi and M. Noori, “A highly-sensitive temperature sensor based on GeO2–SiO2 long period fiber grating,” Phys. Scr. 96(1), 015505 (2020).
[Crossref]

Oh, K.

S. Song, A. Jung, S. Hong, and K. Oh, “Strain-Insensitive Biocompatible Temperature Sensor Based on DNA Solid Film on an Optical Microfiber,” IEEE Photonics Technol. Lett. 31(24), 1925–1928 (2019).
[Crossref]

Pang, B.

B. Pang, Z. Gu, Q. Ling, W. Wu, and Y. Zhou, “Simultaneous measurement of temperature and surrounding refractive index by superimposed coated long period fiber grating and fiber Bragg grating sensor based on mode barrier region,” Optik 220, 165136 (2020).
[Crossref]

Peng, B. J.

R. H. Fan, L. Q. Li, C. C. Wang, Y. D. Deng, X. X. Lv, Z. J. Ren, J. G. Shen, and B. J. Peng, “Interference-Type High-Sensitivity Temperature Sensor Based on the Photosensitive Fiber Microsphere,” IEEE Sens. J. 19(24), 11941–11945 (2019).
[Crossref]

Peng, F.

Popenda, M. A.

H. I. Stawska and M. A. Popenda, “Refractive Index Sensors Based on Long-Period Grating in a Negative Curvature Hollow-Core Fiber,” Sensors 21(5), 1803 (2021).
[Crossref]

Porraz-Culebro, T. E.

Qing-jun, M.

X. D. Li Qiu-shun, M. Qing-jun, Y. Jun-hui, S. Jian-guo, and D. Wen-fei, “Design and test of transmission mode measurement device based on long period fiber grating with a single end face,” Chinese Opt. 10(6), 783–789 (2017).
[Crossref]

Ren, Z. J.

R. H. Fan, L. Q. Li, C. C. Wang, Y. D. Deng, X. X. Lv, Z. J. Ren, J. G. Shen, and B. J. Peng, “Interference-Type High-Sensitivity Temperature Sensor Based on the Photosensitive Fiber Microsphere,” IEEE Sens. J. 19(24), 11941–11945 (2019).
[Crossref]

Rothhardt, M.

Salceda-Delgado, G.

Shen, J. G.

R. H. Fan, L. Q. Li, C. C. Wang, Y. D. Deng, X. X. Lv, Z. J. Ren, J. G. Shen, and B. J. Peng, “Interference-Type High-Sensitivity Temperature Sensor Based on the Photosensitive Fiber Microsphere,” IEEE Sens. J. 19(24), 11941–11945 (2019).
[Crossref]

Shen, Y.

S. Yao, Y. Shen, Y. Wu, W. Jin, and S. Jian, “Strain-insensitive temperature sensor based on a few-mode dual-concentric-core fiber,” Opt. Laser Technol. 111, 95–99 (2019).
[Crossref]

Shi, J.

S. S. Zhang, C. Q. Fang, C. Zhang, J. Shi, J. F. Zhao, Y. G. Liu, E. D. Gu, and J. Q. Yao, “A Compact Ultra-Long Period Fiber Grating Based on Cascading Up-Tapers,” IEEE Sens. J. 20, 8552–8558 (2020).
[Crossref]

Shu, X. W.

Sierra-Hernandez, J. M.

Song, S.

S. Song, A. Jung, S. Hong, and K. Oh, “Strain-Insensitive Biocompatible Temperature Sensor Based on DNA Solid Film on an Optical Microfiber,” IEEE Photonics Technol. Lett. 31(24), 1925–1928 (2019).
[Crossref]

Song, X.

Spittel, R.

Stawska, H. I.

H. I. Stawska and M. A. Popenda, “Refractive Index Sensors Based on Long-Period Grating in a Negative Curvature Hollow-Core Fiber,” Sensors 21(5), 1803 (2021).
[Crossref]

Sun, C.

C. Lu, X. Jin, S. Wang, Z. Xiang, C. Sun, X. Chen, Y. Ma, Q. Zhu, C. Tong, T. Geng, W. Sun, and L. Yuan, “High Torsion Sensitivity Sensor Based on LPFG With Unique Geometric Structure,” IEEE Sens. J. 21(5), 6217–6223 (2021).
[Crossref]

S. Zhang, T. Geng, H. Niu, X. Li, Y. Yan, C. Sun, S. Deng, Z. Wang, S. Wang, W. Yang, W. Sun, and L. Yuan, “All fiber compact bending sensor with high sensitivity based on a multimode fiber embedded chirped long-period grating,” Opt. Lett. 45(15), 4172–4175 (2020).
[Crossref]

S. Zhang, S. Deng, T. Geng, C. Sun, H. Niu, X. Li, Z. Wang, X. Li, Y. Ma, W. Yang, C. Tong, and L. Yuan, “A miniature ultra long period fiber grating for simultaneous measurement of axial strain and temperature,” Opt. Laser Technol. 126, 106121 (2020).
[Crossref]

S. Zhang, X. Li, H. Niu, Q. Yan, C. Sun, F. Peng, Y. Ma, K. Zhang, T. Geng, W. Yang, W. Sun, and L. Yuan, “Few-mode fiber-embedded long-period fiber grating for simultaneous measurement of refractive index and temperature,” Appl. Opt. 59(29), 9248–9253 (2020).
[Crossref]

W. Liu, C. Sun, T. Geng, X. Jin, X. Chen, L. Yu, C. Zhao, X. Bai, S. Duan, H. Du, and L. Yuan, “A New Spring-Shaped Long-Period Fiber Grating With High Strain Sensitivity,” IEEE Photonics Technol. Lett. 31(14), 1163–1166 (2019).
[Crossref]

Sun, W.

Sun, X.

J. Zhao, H. Wang, and X. Sun, “Study on the performance of polarization maintaining fiber temperature sensor based on tilted fiber grating,” Measurement 168, 108421 (2021).
[Crossref]

Tian, B.

N. Zhao, Q. Lin, K. Yao, F. Zhang, B. Tian, F. Chen, and Z. Jiang, “Simultaneous Measurement of Temperature and Refractive Index Using High Temperature Resistant Pure Quartz Grating Based on Femtosecond Laser and HF Etching,” Materials 14(4), 1028 (2021).
[Crossref]

Tian, D.

X. Cao, D. Tian, Y. Liu, L. Zhang, and T. Wang, “Sensing Characteristics of Helical Long-Period Gratings Written in the Double-Clad Fiber by CO2 Laser,” IEEE Sens. J. 18(18), 7481–7485 (2018).
[Crossref]

Tong, C.

C. Lu, X. Jin, S. Wang, Z. Xiang, C. Sun, X. Chen, Y. Ma, Q. Zhu, C. Tong, T. Geng, W. Sun, and L. Yuan, “High Torsion Sensitivity Sensor Based on LPFG With Unique Geometric Structure,” IEEE Sens. J. 21(5), 6217–6223 (2021).
[Crossref]

S. Zhang, S. Deng, T. Geng, C. Sun, H. Niu, X. Li, Z. Wang, X. Li, Y. Ma, W. Yang, C. Tong, and L. Yuan, “A miniature ultra long period fiber grating for simultaneous measurement of axial strain and temperature,” Opt. Laser Technol. 126, 106121 (2020).
[Crossref]

Toral-Acosta, D.

Wang, C. C.

R. H. Fan, L. Q. Li, C. C. Wang, Y. D. Deng, X. X. Lv, Z. J. Ren, J. G. Shen, and B. J. Peng, “Interference-Type High-Sensitivity Temperature Sensor Based on the Photosensitive Fiber Microsphere,” IEEE Sens. J. 19(24), 11941–11945 (2019).
[Crossref]

Wang, H.

J. Zhao, H. Wang, and X. Sun, “Study on the performance of polarization maintaining fiber temperature sensor based on tilted fiber grating,” Measurement 168, 108421 (2021).
[Crossref]

Wang, Q.

M. Luo and Q. Wang, “Fabrication and sensing characteristics of arc-induced long-period fiber gratings based on thin-cladding fiber,” Alexandria Eng. J. 59(5), 3681–3686 (2020).
[Crossref]

Wang, S.

J. Ma, S. Wu, H. Cheng, X. Yang, S. Wang, and P. Lu, “Sensitivity-enhanced temperature sensor based on encapsulated S-taper fiber Modal interferometer,” Opt. Laser Technol. 139, 106933 (2021).
[Crossref]

C. Lu, X. Jin, S. Wang, Z. Xiang, C. Sun, X. Chen, Y. Ma, Q. Zhu, C. Tong, T. Geng, W. Sun, and L. Yuan, “High Torsion Sensitivity Sensor Based on LPFG With Unique Geometric Structure,” IEEE Sens. J. 21(5), 6217–6223 (2021).
[Crossref]

S. Zhang, T. Geng, H. Niu, X. Li, Y. Yan, C. Sun, S. Deng, Z. Wang, S. Wang, W. Yang, W. Sun, and L. Yuan, “All fiber compact bending sensor with high sensitivity based on a multimode fiber embedded chirped long-period grating,” Opt. Lett. 45(15), 4172–4175 (2020).
[Crossref]

Wang, T.

X. Cao, D. Tian, Y. Liu, L. Zhang, and T. Wang, “Sensing Characteristics of Helical Long-Period Gratings Written in the Double-Clad Fiber by CO2 Laser,” IEEE Sens. J. 18(18), 7481–7485 (2018).
[Crossref]

Wang, Z.

S. Zhang, T. Geng, H. Niu, X. Li, Y. Yan, C. Sun, S. Deng, Z. Wang, S. Wang, W. Yang, W. Sun, and L. Yuan, “All fiber compact bending sensor with high sensitivity based on a multimode fiber embedded chirped long-period grating,” Opt. Lett. 45(15), 4172–4175 (2020).
[Crossref]

S. Zhang, S. Deng, T. Geng, C. Sun, H. Niu, X. Li, Z. Wang, X. Li, Y. Ma, W. Yang, C. Tong, and L. Yuan, “A miniature ultra long period fiber grating for simultaneous measurement of axial strain and temperature,” Opt. Laser Technol. 126, 106121 (2020).
[Crossref]

Wen-fei, D.

X. D. Li Qiu-shun, M. Qing-jun, Y. Jun-hui, S. Jian-guo, and D. Wen-fei, “Design and test of transmission mode measurement device based on long period fiber grating with a single end face,” Chinese Opt. 10(6), 783–789 (2017).
[Crossref]

Wu, S.

J. Ma, S. Wu, H. Cheng, X. Yang, S. Wang, and P. Lu, “Sensitivity-enhanced temperature sensor based on encapsulated S-taper fiber Modal interferometer,” Opt. Laser Technol. 139, 106933 (2021).
[Crossref]

Wu, W.

B. Pang, Z. Gu, Q. Ling, W. Wu, and Y. Zhou, “Simultaneous measurement of temperature and surrounding refractive index by superimposed coated long period fiber grating and fiber Bragg grating sensor based on mode barrier region,” Optik 220, 165136 (2020).
[Crossref]

Wu, Y.

S. Yao, Y. Shen, Y. Wu, W. Jin, and S. Jian, “Strain-insensitive temperature sensor based on a few-mode dual-concentric-core fiber,” Opt. Laser Technol. 111, 95–99 (2019).
[Crossref]

Xiang, Z.

C. Lu, X. Jin, S. Wang, Z. Xiang, C. Sun, X. Chen, Y. Ma, Q. Zhu, C. Tong, T. Geng, W. Sun, and L. Yuan, “High Torsion Sensitivity Sensor Based on LPFG With Unique Geometric Structure,” IEEE Sens. J. 21(5), 6217–6223 (2021).
[Crossref]

Xu, X.

X. Xu, M. Luo, J. Liu, and N. Luan, “Fluorinated Polyimide-Film Based Temperature and Humidity Sensor Utilizing Fiber Bragg Grating,” Sensors 20(19), 5469 (2020).
[Crossref]

Xuewen Shu, L. Z.

Yan, Q.

Yan, Y.

Yang, W.

Yang, X.

J. Ma, S. Wu, H. Cheng, X. Yang, S. Wang, and P. Lu, “Sensitivity-enhanced temperature sensor based on encapsulated S-taper fiber Modal interferometer,” Opt. Laser Technol. 139, 106933 (2021).
[Crossref]

Yao, J. Q.

S. S. Zhang, C. Q. Fang, C. Zhang, J. Shi, J. F. Zhao, Y. G. Liu, E. D. Gu, and J. Q. Yao, “A Compact Ultra-Long Period Fiber Grating Based on Cascading Up-Tapers,” IEEE Sens. J. 20, 8552–8558 (2020).
[Crossref]

Yao, K.

N. Zhao, Q. Lin, K. Yao, F. Zhang, B. Tian, F. Chen, and Z. Jiang, “Simultaneous Measurement of Temperature and Refractive Index Using High Temperature Resistant Pure Quartz Grating Based on Femtosecond Laser and HF Etching,” Materials 14(4), 1028 (2021).
[Crossref]

Yao, S.

S. Yao, Y. Shen, Y. Wu, W. Jin, and S. Jian, “Strain-insensitive temperature sensor based on a few-mode dual-concentric-core fiber,” Opt. Laser Technol. 111, 95–99 (2019).
[Crossref]

Yu, D.

Yu, L.

W. Liu, C. Sun, T. Geng, X. Jin, X. Chen, L. Yu, C. Zhao, X. Bai, S. Duan, H. Du, and L. Yuan, “A New Spring-Shaped Long-Period Fiber Grating With High Strain Sensitivity,” IEEE Photonics Technol. Lett. 31(14), 1163–1166 (2019).
[Crossref]

Yuan, L.

C. Lu, X. Jin, S. Wang, Z. Xiang, C. Sun, X. Chen, Y. Ma, Q. Zhu, C. Tong, T. Geng, W. Sun, and L. Yuan, “High Torsion Sensitivity Sensor Based on LPFG With Unique Geometric Structure,” IEEE Sens. J. 21(5), 6217–6223 (2021).
[Crossref]

S. Zhang, T. Geng, H. Niu, X. Li, Y. Yan, C. Sun, S. Deng, Z. Wang, S. Wang, W. Yang, W. Sun, and L. Yuan, “All fiber compact bending sensor with high sensitivity based on a multimode fiber embedded chirped long-period grating,” Opt. Lett. 45(15), 4172–4175 (2020).
[Crossref]

S. Zhang, X. Li, H. Niu, Q. Yan, C. Sun, F. Peng, Y. Ma, K. Zhang, T. Geng, W. Yang, W. Sun, and L. Yuan, “Few-mode fiber-embedded long-period fiber grating for simultaneous measurement of refractive index and temperature,” Appl. Opt. 59(29), 9248–9253 (2020).
[Crossref]

S. Zhang, S. Deng, T. Geng, C. Sun, H. Niu, X. Li, Z. Wang, X. Li, Y. Ma, W. Yang, C. Tong, and L. Yuan, “A miniature ultra long period fiber grating for simultaneous measurement of axial strain and temperature,” Opt. Laser Technol. 126, 106121 (2020).
[Crossref]

W. Liu, C. Sun, T. Geng, X. Jin, X. Chen, L. Yu, C. Zhao, X. Bai, S. Duan, H. Du, and L. Yuan, “A New Spring-Shaped Long-Period Fiber Grating With High Strain Sensitivity,” IEEE Photonics Technol. Lett. 31(14), 1163–1166 (2019).
[Crossref]

Zhang, C.

S. S. Zhang, C. Q. Fang, C. Zhang, J. Shi, J. F. Zhao, Y. G. Liu, E. D. Gu, and J. Q. Yao, “A Compact Ultra-Long Period Fiber Grating Based on Cascading Up-Tapers,” IEEE Sens. J. 20, 8552–8558 (2020).
[Crossref]

Zhang, F.

N. Zhao, Q. Lin, K. Yao, F. Zhang, B. Tian, F. Chen, and Z. Jiang, “Simultaneous Measurement of Temperature and Refractive Index Using High Temperature Resistant Pure Quartz Grating Based on Femtosecond Laser and HF Etching,” Materials 14(4), 1028 (2021).
[Crossref]

Zhang, K.

Zhang, L.

X. Cao, D. Tian, Y. Liu, L. Zhang, and T. Wang, “Sensing Characteristics of Helical Long-Period Gratings Written in the Double-Clad Fiber by CO2 Laser,” IEEE Sens. J. 18(18), 7481–7485 (2018).
[Crossref]

X. W. Shu, L. Zhang, and I. Bennion, “Sensitivity characteristics near the dispersion turning points of long-period fiber gratings in B/Ge codoped fiber,” Opt. Lett. 26(22), 1755–1757 (2001).
[Crossref]

Zhang, S.

Zhang, S. S.

S. S. Zhang, C. Q. Fang, C. Zhang, J. Shi, J. F. Zhao, Y. G. Liu, E. D. Gu, and J. Q. Yao, “A Compact Ultra-Long Period Fiber Grating Based on Cascading Up-Tapers,” IEEE Sens. J. 20, 8552–8558 (2020).
[Crossref]

Zhao, C.

W. Liu, C. Sun, T. Geng, X. Jin, X. Chen, L. Yu, C. Zhao, X. Bai, S. Duan, H. Du, and L. Yuan, “A New Spring-Shaped Long-Period Fiber Grating With High Strain Sensitivity,” IEEE Photonics Technol. Lett. 31(14), 1163–1166 (2019).
[Crossref]

Zhao, J.

J. Zhao, H. Wang, and X. Sun, “Study on the performance of polarization maintaining fiber temperature sensor based on tilted fiber grating,” Measurement 168, 108421 (2021).
[Crossref]

Zhao, J. F.

S. S. Zhang, C. Q. Fang, C. Zhang, J. Shi, J. F. Zhao, Y. G. Liu, E. D. Gu, and J. Q. Yao, “A Compact Ultra-Long Period Fiber Grating Based on Cascading Up-Tapers,” IEEE Sens. J. 20, 8552–8558 (2020).
[Crossref]

Zhao, N.

N. Zhao, Q. Lin, K. Yao, F. Zhang, B. Tian, F. Chen, and Z. Jiang, “Simultaneous Measurement of Temperature and Refractive Index Using High Temperature Resistant Pure Quartz Grating Based on Femtosecond Laser and HF Etching,” Materials 14(4), 1028 (2021).
[Crossref]

Zhao, X.

Zhou, Y.

B. Pang, Z. Gu, Q. Ling, W. Wu, and Y. Zhou, “Simultaneous measurement of temperature and surrounding refractive index by superimposed coated long period fiber grating and fiber Bragg grating sensor based on mode barrier region,” Optik 220, 165136 (2020).
[Crossref]

Zhu, Q.

C. Lu, X. Jin, S. Wang, Z. Xiang, C. Sun, X. Chen, Y. Ma, Q. Zhu, C. Tong, T. Geng, W. Sun, and L. Yuan, “High Torsion Sensitivity Sensor Based on LPFG With Unique Geometric Structure,” IEEE Sens. J. 21(5), 6217–6223 (2021).
[Crossref]

Alexandria Eng. J. (1)

M. Luo and Q. Wang, “Fabrication and sensing characteristics of arc-induced long-period fiber gratings based on thin-cladding fiber,” Alexandria Eng. J. 59(5), 3681–3686 (2020).
[Crossref]

Appl. Opt. (2)

Chinese Opt. (1)

X. D. Li Qiu-shun, M. Qing-jun, Y. Jun-hui, S. Jian-guo, and D. Wen-fei, “Design and test of transmission mode measurement device based on long period fiber grating with a single end face,” Chinese Opt. 10(6), 783–789 (2017).
[Crossref]

IEEE Photonics Technol. Lett. (3)

S. Song, A. Jung, S. Hong, and K. Oh, “Strain-Insensitive Biocompatible Temperature Sensor Based on DNA Solid Film on an Optical Microfiber,” IEEE Photonics Technol. Lett. 31(24), 1925–1928 (2019).
[Crossref]

S. Lei, C. Kin Seng, and L. Chao, “CO2-Laser-Induced Long-Period Gratings in Graded-Index Multimode Fibers for Sensor Applications,” IEEE Photonics Technol. Lett. 18(1), 190–192 (2006).
[Crossref]

W. Liu, C. Sun, T. Geng, X. Jin, X. Chen, L. Yu, C. Zhao, X. Bai, S. Duan, H. Du, and L. Yuan, “A New Spring-Shaped Long-Period Fiber Grating With High Strain Sensitivity,” IEEE Photonics Technol. Lett. 31(14), 1163–1166 (2019).
[Crossref]

IEEE Sens. J. (4)

C. Lu, X. Jin, S. Wang, Z. Xiang, C. Sun, X. Chen, Y. Ma, Q. Zhu, C. Tong, T. Geng, W. Sun, and L. Yuan, “High Torsion Sensitivity Sensor Based on LPFG With Unique Geometric Structure,” IEEE Sens. J. 21(5), 6217–6223 (2021).
[Crossref]

R. H. Fan, L. Q. Li, C. C. Wang, Y. D. Deng, X. X. Lv, Z. J. Ren, J. G. Shen, and B. J. Peng, “Interference-Type High-Sensitivity Temperature Sensor Based on the Photosensitive Fiber Microsphere,” IEEE Sens. J. 19(24), 11941–11945 (2019).
[Crossref]

S. S. Zhang, C. Q. Fang, C. Zhang, J. Shi, J. F. Zhao, Y. G. Liu, E. D. Gu, and J. Q. Yao, “A Compact Ultra-Long Period Fiber Grating Based on Cascading Up-Tapers,” IEEE Sens. J. 20, 8552–8558 (2020).
[Crossref]

X. Cao, D. Tian, Y. Liu, L. Zhang, and T. Wang, “Sensing Characteristics of Helical Long-Period Gratings Written in the Double-Clad Fiber by CO2 Laser,” IEEE Sens. J. 18(18), 7481–7485 (2018).
[Crossref]

J. Lightwave Technol. (3)

J. Nanosci. Nanotechnol. (1)

S. J. Jeong, J. Kim, S. Choi, S. L. Lee, M. S. Kim, D. K. Kim, and Y. W. Lee, “Simultaneous Measurement of Bending and Temperature Using Long-Period Fiber Grating Inscribed on Polarization-Maintaining Fiber with CO2 Laser,” J. Nanosci. Nanotechnol. 20(1), 285–292 (2020).
[Crossref]

Materials (1)

N. Zhao, Q. Lin, K. Yao, F. Zhang, B. Tian, F. Chen, and Z. Jiang, “Simultaneous Measurement of Temperature and Refractive Index Using High Temperature Resistant Pure Quartz Grating Based on Femtosecond Laser and HF Etching,” Materials 14(4), 1028 (2021).
[Crossref]

Measurement (1)

J. Zhao, H. Wang, and X. Sun, “Study on the performance of polarization maintaining fiber temperature sensor based on tilted fiber grating,” Measurement 168, 108421 (2021).
[Crossref]

Opt. Express (2)

Opt. Laser Technol. (3)

S. Zhang, S. Deng, T. Geng, C. Sun, H. Niu, X. Li, Z. Wang, X. Li, Y. Ma, W. Yang, C. Tong, and L. Yuan, “A miniature ultra long period fiber grating for simultaneous measurement of axial strain and temperature,” Opt. Laser Technol. 126, 106121 (2020).
[Crossref]

J. Ma, S. Wu, H. Cheng, X. Yang, S. Wang, and P. Lu, “Sensitivity-enhanced temperature sensor based on encapsulated S-taper fiber Modal interferometer,” Opt. Laser Technol. 139, 106933 (2021).
[Crossref]

S. Yao, Y. Shen, Y. Wu, W. Jin, and S. Jian, “Strain-insensitive temperature sensor based on a few-mode dual-concentric-core fiber,” Opt. Laser Technol. 111, 95–99 (2019).
[Crossref]

Opt. Lett. (2)

Optik (1)

B. Pang, Z. Gu, Q. Ling, W. Wu, and Y. Zhou, “Simultaneous measurement of temperature and surrounding refractive index by superimposed coated long period fiber grating and fiber Bragg grating sensor based on mode barrier region,” Optik 220, 165136 (2020).
[Crossref]

Phys. Scr. (1)

M. Lotfi and M. Noori, “A highly-sensitive temperature sensor based on GeO2–SiO2 long period fiber grating,” Phys. Scr. 96(1), 015505 (2020).
[Crossref]

Sensors (2)

X. Xu, M. Luo, J. Liu, and N. Luan, “Fluorinated Polyimide-Film Based Temperature and Humidity Sensor Utilizing Fiber Bragg Grating,” Sensors 20(19), 5469 (2020).
[Crossref]

H. I. Stawska and M. A. Popenda, “Refractive Index Sensors Based on Long-Period Grating in a Negative Curvature Hollow-Core Fiber,” Sensors 21(5), 1803 (2021).
[Crossref]

Data availability

Data underlying the results presented in this paper are not publicly available at this time but may be obtained from the authors upon reasonable request.

Cited By

Optica participates in Crossref's Cited-By Linking service. Citing articles from Optica Publishing Group journals and other participating publishers are listed here.

Alert me when this article is cited.


Figures (9)

Fig. 1.
Fig. 1. The schematic diagram of (a) the sensing structure; (b) preparation process of the sensing structure; (c) preparation device and microscopic images.
Fig. 2.
Fig. 2. The diagram of the light field distribution of (a) the SI-MMF; (b) the GI-MMF; (c) the core energy ratio along the transmission distance.
Fig. 3.
Fig. 3. The transmission spectra of the EULPFG with different (a) GI-MMF lengths; (b) SMF lengths.
Fig. 4.
Fig. 4. The diagram of (a) light field distribution; (b) simulated spectrum evolution of the EULPFG.
Fig. 5.
Fig. 5. The diagram of experimental spectrum evolution of the EULPFG.
Fig. 6.
Fig. 6. Schematic diagram of the integrated measuring device.
Fig. 7.
Fig. 7. The change of transmission spectra under the different temperatures and the linear fitting between the wavelength and temperature.
Fig. 8.
Fig. 8. The variation of resonant peak and linear relationship between (a) the RI and wavelength; (b) the strain and wavelength; (c) the curvature and wavelength.
Fig. 9.
Fig. 9. Calculated variation of the resonance wavelength with periods.

Equations (6)

Equations on this page are rendered with MathJax. Learn more.

n 2 ( r ) = n 1 2 ( n 1 2 n 2 2 ) ( a r ) 2 , a < r
λ r e s = [ n c o e f f n c l e f f ( r ) ] Λ ,
d λ r e s d T = ( d n e f f c o d T d n e f f c l , m d T ) Λ + ( n e f f c o n e f f c l , m ) d Λ d T
d λ r e s d ε = λ r e s m γ m ( 1 + Γ s t r a i n m )
d λ r e s d Λ = γ m n e f f c o n e f f c l , m
d λ r e s d n = λ r e s m γ m Γ R I m

Metrics