Abstract

We experimentally demonstrate tunable multiple-idler wavelength broadcasting of a signal to selective channels for wavelength division multiplexing (WDM). This is based on cascaded χ(2) nonlinear mixing process in a novel multiple-QPM 10-mm-long periodically poled LiNbO3 having an aperiodic domain in the center. The idlers’ spacing is varied utilizing detuning of the pump wavelength within the SHG bandwidth. The temperature-assisted tuning of QPM pump wavelengths allows shifting the idlers together to different set of WDM channels. Our experimental results indicate that an overall idler wavelength shift of less than 10 nm realized by selecting pump wavelengths via temperature tuning, is sufficient to cover up to 40 WDM channels for multiple idlers broadcasting.

© 2012 OSA

1. Introduction

With ever-increasing data transmission capacity, WDM networks require tunable wavelength broadcasting by replicating a signal to several channels to facilitate flexible routing, switching and dynamic reconfiguration of the information carried by different channels. Owing to their high speed, large bandwidth, large signal-to-noise ratio, transparency to signal format and so on, all-optical quasi-phase-matched (QPM) wavelength converters based on second-order nonlinearity in periodically poled lithium niobate (PPLN) have attracted increasing attention [13]. Over the past decade, research on cascaded second-order nonlinear interactions in QPM-PPLN has been growing fast to satisfy the needs of high speed and large capacity optical networks [1,4,5]. Achieving wavelength broadcasting in these QPM devices is also useful for several applications such as video distribution and teleconferencing [1,6,7].

Frequency conversion of an input signal at frequency ωs to an idler frequency ωc located in the same band using a pump frequency ωp such that ωc = 2ωp - ωs, has been realized using cascaded processes of second harmonic generation and difference frequency generation (cSHG/DFG) [8]. Wavelength conversion based on cascaded sum-frequency generation (SFG) and DFG to generate the idler at ωc = ωp1 + ωp2 - ωs is advantageous for ultrafast optical signal processing [2,7,911]. However, the phase matching criteria of a periodic QPM structure limits the SHG bandwidth. This restricts the tunability of a cSHG/DFG frequency conversion and eventually the broadcasting process. To solve the bandwidth problem, a type-1 QPM with broad SHG bandwidth of 25 nm in an MgO-PPLN was already demonstrated [12]. Also by selecting the two pumps for cSFG/DFG closely spaced within the 1.5-μm band, one signal was simultaneously broadcast to seven fixed peaks [1]. Based on difference frequency mixing, Asobe et. al. and Chou et. al. demonstrated multiple-QPM-based wavelength generation in engineered phase-modulated QPM LN waveguides [13,14]. In another case, simultaneous multicasting of 2 multiplexed signals using cSFG/DFG in a uniform single-QPM PPLN waveguide was achieved, however, it required seven CW pumps to generate seven idlers of the multiplexed signal [15]. Although for practical optical communication networks, the tunability of multiple-QPM-based wavelength broadcasting is essential to provide variable number and location of output channels, it has not yet been implemented. Further, reduced efficiency owing to the use of non-preferred nonlinear coefficient (d31) in type-1 QPM needs to be overcome. Our solution for a tunable wavelength broadcasting to several channels is to use a structure with type-0 multiple QPM-SHG, which can be tuned by varying the temperature of the crystal to obtain efficient multiple peaks in different wavelengths [16]. Unlike using a type-1 process, utilizing a type-0 process with appropriate temperature tuning, we can benefit from both tunable multiple-QPM bandwidth and high-efficiency conversion.

In this paper, first, we demonstrate variable SHG-SFG in a novel type-0 multiple-QPM structure using an engineered PPLN to generate one, two or three SH-SF peaks and second, its application in multiple-wavelength broadcasting by DFG mixing of a signal with the generated SH-SF peaks. Tunability of wavelength broadcasting to three idlers with the desired spacing and variable position of the destination channel for WDM is achieved by detuning the two pumps within the SFG bandwidth and making use of the dependence of the QPM efficiency curves on temperature tuning of a PPLN device for the assignment of the pump wavelengths. This scheme is very promising for enhancing the capabilities of existing WDM optical communication systems.

2. Multiple QPM structure in a type-0 PPLN

Besides the engineering of the effective nonlinearity, the advantage of QPM in materials such as lithium niobate (LN) is the access to its large d33 nonlinear coefficient, which cannot be realized by birefringent phase-matching. In type-0 QPM process, the interacting fields propagate as extraordinary waves when polarized along the z-axis ase+ee. An engineered phase-reversal QPM structure, used in our experiments is shown in Fig. 1 . This device has been fabricated by the room temperature electric field poling method [17]. The period of the 1-cm-long PPLN is Λ = 18.5 μm with an aperiodic domain of width Λ in the center. For a length, l of the grating and aperiodic domain in the middle, l/2 of device, the variation of effective nonlinear coefficient along length, x is written as [18]:

κ(x)=deffsin(2πxΛ)[rect(xl/4l/2)rect(x3l/4l/2)]
where rect is the rectangular function. The SH amplitude, A2 of the multiple-QPM PPLN device is then given by:
A2(q)=iA12ldeffeiπl(q±1Λ)sin2(π2l(q±1Λ))π2l(q±1Λ)
where A1 is the FH amplitude, q=(k2ω2kω)/2π is the phase mismatch, kω,2ω are the wave vectors of FH and SH, and deff is the effective nonlinearity. The intensity, I can be calculated using I=12cε0n|A2|2, where c is the speed of light, ε0is the free space permittivity, and n is the refractive index of the medium. This analysis will give two QPM peaks in SH spectrum with the maximum efficiencies at the pump frequencies ωp1 and ωp2. In case of cascaded SHG/DFG process using a signal frequency ωs and pump at either of ωp1,p2 the idlers will be generated at 2ωp1,p2ωs. When two pumps are used, we also get cascaded SFG/DFG process generating an additional idler at ωp1+ωp2ωs.

 

Fig. 1 Experimental setup for cSFG/DFG with two pumps and a signal, PC: Polarization Controller, OSA: Optical Spectrum Analyzer. For SFG, just the two pump wavelengths are coupled into the setup. PPLN with a central aperiodic domain having width equal to size of the device period is shown.

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The temperature acceptance bandwidth for a QPM process can be obtained using the phase matching sinc term of SHG conversion efficiency considering the Sellmeier relation [19], which depicts the refractive index dependence on the crystal temperature, and wavelength of the incident light. As a type-0 process has a wider temperature acceptance bandwidth than a type-1 process (o+oe)with proper tuning of temperature, the wavelength acceptance bandwidth in type-0 structure can be further improved.

2.1 Experimental setup

Figure 1 shows the experimental setup used for c(SHG-SFG)/DFG in which two tunable lasers are employed as pumps, operating within the C-band. They are combined by a WDM coupler and then amplified by a Pritel high-power EDFA. The amplified lightwaves, passing through a polarization controller are con-focally focused using a lens into a 10-mm-long bulk z-cut multiple-QPM PPLN fabricated by room-temperature electric-field poling [17]. The phase-reversal PPLN sample is temperature controlled for tuning the operating wavelengths and maximizing the conversion efficiency. In our experiments, we have observed a temperature tuning coefficient of 0.3 nm/°C for the PPLN device. A 9.5 dB filter is used for high input powers beyond 100 mW to avoid damaging the detector. The waist of input lights is ω0=1.83mmwhich is focused to a beam-waist of ωf=30μm in the center of the PPLN with the length l, using a 10-cm focal length lens. The output lights are coupled to a spectrum analyzer via a 30x Newport objective and a multimode fiber, for which the coupling loss of the setup is 1.5 dB.

2.2 SHG and SFG in multiple-QPM bulk PPLN

The maximum SHG power for each QPM peak of the phase-reversal PPLN in the plane wave approximation can be calculated using the Eq.: PSHG=8πdeff2ε0cn21nSHλ12ωf2P12l2 [20,21]. Here, the pump wavelength is λ1=1538nm,the effective nonlinearity coefficient of 2-peak QPM LN is: deff=2d33/π=10.6pm/V, the free space permittivity is ε0=8.85×10-12F/m, n1 and nSH are the refractive indices of LN at the FH and the SH wavelengths, respectively. For an input pump power P1 = 90 mW, theoretical calculation gives a peak SHG power PSHG = 0.042 mW or an efficiency of −33.32 dB. Figure 2(a) (dashed curve) illustrates the normalized multiple-peak SH power for the characterized PPLN device showing two major QPM peaks for the pump wavelength at 1536.1 nm and 1538.2 nm at 80°C, while the solid-curve depicts the theoretically-simulated normalized SHG plot for such a device based on Eq. (2). The dual peak nature is attributed to the phase reversal due to the aperiodic domain in the center of the PPLN structure. Further a small deviation in the size of aperiodic domain from the poling period leads to the asymmetric peaks.

 

Fig. 2 (a) SH power vs. pump wavelength, theoretical (solid black) and experimentally observed (dotted, red) plots for the 2-peak QPM structure shown. (b) Spectra of multiple SHG-SFG for the different cases of 2 SH and 1 SF output (blue dashed); 1SH and 1SF (dash-dotted red curve); 1SH peak (green solid trace)

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The maximum peak power at 1538.2 nm is 0.04 mW giving an efficiency of −33.58 dB (0.1%/W) which is in accordance with the calculated value. When two pumps are set at each of the two QPM wavelengths, they result in two SH and one SF peak in between, however, with uneven powers. This is shown in Fig. 2(b) (blue dashed trace) with the input wavelengths of 1536.1 nm and 1538.2 nm. Tuning one of the lasers to the dip (1536.88 nm) in the center of two-peak SHG spectrum of Fig. 2(a) results in the suppression of the short-wavelength SH peak as shown in Fig. 2(b) by red dotted trace; the two peaks (1 SF, 1 SH) obtained here are separated by 0.3 nm. The peak separation and relative efficiency are varied by slightly detuning the input wavelengths. By moving either of the lasers out of the SH and SF bandwidth, a single SH peak (e.g. Figure 2(b) green trace) is achieved.

The SH and SF powers were equalized by slightly detuning the wavelength and varying the power of input pumps, as illustrated in Fig. 3(a) . Thus, the two pumps are set at 1536.14 nm and 1536.28 nm. Figure 3(b) demonstrates the three peaks of SH-SF response of the fabricated PPLN device at two different temperatures wherein the QPM condition of the pumps have changed, due to temperature dependence of effective refractive index. A constant 1.2-nm wavelength difference of pumps is maintained. The violet solid curve shows the three SH-SF peaks when the input pump wavelengths are set at 1537.3 nm and 1538.5 nm with the device temperature at 81.5 °C; the orange dashed trace depicts the three wavelength-shifted SH-SF peaks at 84.5 °C when the two pumps are set at 1538.5 nm and 1539.7 nm. Thus, when each pump is shifted by 1.2 nm with the appropriate temperature tuning, it leads to a shift of 0.6 nm in the SH-SF spectrum.

 

Fig. 3 (a) Spectrum of multiple SHG-SFG showing equalized peak powers achieved by pump detuning, mutual spacing of the peaks is 0.55 nm. (b) Spectra of three SH-SF peaks showing 0.6 nm peak-wavelength shift over a 3°C temperature difference when the two pump wavelengths were simultaneously shifted from 1537.3 nm and 1538.5 nm to 1538.5 nm and 1539.7 nm.

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3. Cascaded SHG-SFG/DFG in multiple-QPM bulk PPLN

Wavelength conversion based on cascaded second order nonlinear interaction in QPM devices are attractive for signal processing in all-optical networks. In a cascaded SFG/DFG process two pump beams at frequencies ωp1 and ωp2 are used to generate a wave at frequency ωSF = ωp1 + ωp2 through the SFG process, which then combines with a signal wave ωs in a DFG process to generate the converted idler at ωc = ωp1 + ωp2-ωs [810,22]. To realize efficient wavelength conversions, the SFG and DFG processes must satisfy the following QPM conditions respectively:

nSFωSF/cn1ωp1/cn2ωp2/c=2π/Λ,
nSFωSF/cnsωs/cncωc/c=2π/Λ,
where nSF, np1, np2, ns, nc are the refractive indices of the PPLN at the sum-frequency wave, two pumps, signal and idler frequencies, c is the speed of the light in vacuum, and Λ is the period of the grating. In the experimental setup for wavelength conversion we use a fixed-wavelength laser as a signal along with two tunable lasers as pump sources set at the 2 QPM wavelengths of the engineered PPLN device, shown in Fig. 1. Difference frequency mixing of a C-band signal wavelength with the multiple SH-SF peaks generated from the two pumps in the C-band gives multiple idlers in the same band. The output power of the SF wave is twice the SH wave for equal-power pumps; e.g. for the two pumps with powers of 182 mW and 145 mW, respectively, the SF power obtained is PSFG=16πdeff2P1P2l2/(ε0cn1n2nSFλ1λ2ωf2) and is equal to 2κP1P2l2=2.63dBm.The cascaded SFG/DFG output can then be calculated as: PSFG/DFG=κPSFGPsignall2=38.2dBm, considering the input PSFG = average of SFG over half-length of the PPLN and Psignal = 14.3 dBm. The experimentally observed efficiency of ~53.2dBis thus comparable with the calculated efficiency = −52.5 dB.

4. Tuning the idler spacing by pump detuning

The schematic of the mutual spacing of the three broadcast idlers via cSFG-SHG/DFG by employing pump detuning in the SFG bandwidth is represented in Fig. 4(a) , when the change in the pump wavelengths is reflected identically in the idlers. To demonstrate this experimentally, we set the two pumps at each of the two QPM wavelengths (1536.1 nm and 1538.2 nm, at 80°C) resulting in two SH peaks and one SF peak in between. DF mixing of a signal wavelength at 1545.3 nm with these three SH-SF peaks gives three idlers. The channels for the WDM network considered here, are separated by 50 GHz (0.4 nm) in the C band. Keeping the signal wavelength fixed, we obtain the desired wavelength spacing between the idlers by the tuning of pump wavelengths around the two QPM peaks of SH wavelengths. We have successfully varied the spacing from 0.4 nm to 4 nm between the idlers in steps of 0.4 nm, without registering significant loss in the idler efficiency, so that the idlers can be directed over 11 adjacent WDM channels on either side of the central idler. For example, Fig. 4(b) illustrates the cases for idler spacing of 0.4 nm, 1.2 nm, 2.4 nm and 3.6 nm, while keeping the signal wavelength fixed. Employing a chirped 2-QPM device in which we get broader bandwidth of 2-QPM SHG response, we can thus cover many more WDM channels.

 

Fig. 4 (a) Scheme for tunable broadcasting of a signal into three idlers by detuning of the pump wavelengths (b) Spectral variation of idler spacing with detuning of both pump wavelengths.

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In the above case, we detuned both the pumps towards or away from their respective QPM peak centers by same frequency detuning δω (i.e, ωp1δω and ωp2+δω), so that their SFG remains fixed at ωp1+ωp2 after detuning and hence the corresponding central idler remains fixed in one channel. The idlers on either side however shift as they correspond to the SHG of the two pumps and the two new WDM channels are now broadcast on either side of the same central idler (channel). There are, however, two other possibilities which require fixing one of the two pumps and tuning the other so that either the left or the right idler lies in same channel while the other two are navigated to subsequent channels as shown in the schematic of Fig. 5(a) . We performed these experiments, as illustrated in Fig. 5(b) where the idler spacing of 0.4 nm, 2.0 nm and 3.6 nm has been obtained by tuning one pump around ω2 while keeping the frequencies of signal and another pump fixed at ωs and ω1, respectively.

 

Fig. 5 (a) Scheme for tunable broadcasting of a signal into three idlers by detuning of pump wavelength. (b) Spectral variation of idler spacing with pump wavelengths separation by tuning just one pump wavelength.

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5. Tuning the idler position with temperature tuning

As we pointed out earlier, the number of channels across which the multiple-idlers can be swept depends on the SH bandwidth of the device. It is advantageous to have a chirped device in such a situation. However, employing temperature tunability to shift the QPM peaks will provide the desired flexibility and tunability for directing idlers across all WDM channels, as detailed in the following. Figure 6(a) shows a schematic of the temperature-assisted tunable broadcasting of a signal into three idlers based on cascaded SHG-SFG/DFG in our proposed PPLN device. The phase-matched wavelengths for the QPM processes in PPLN vary due to temperature dependence of the refractive indexes given by the Sellmeier Eq [19]. The pumps can be tuned to a longer wavelength by increasing the temperature from T1 to T2 and thereby tuning the idlers to longer wavelengths. For example, considering two pumps with constant 1.2-nm wavelength spacing at T1, the three-idler broadcasting will place the idlers at WDM channels 1, 4 and 7. Increasing the temperature to T2 by 4.8°C for a new tuning of the pump wavelengths (shift of 1.6 nm) will locate the idlers at the next channels 5, 8 and 11; and so on.

 

Fig. 6 (a) Scheme for tunable broadcasting of a signal into three idlers by temperature-assisted pump-wavelength tuning. (b) Tunable triple-idler broadcasting of a signal at 1545.27 nm with shifting the two-pump wavelengths at 1536.95 nm and 1538.15 nm by + 1.6 nm, + 3 nm and + 4.4 nm and simultaneous temperature tuning from 78.2°C by + 4.8°C, + 8.3°C and + 10.8°C.

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Figure 6(b) shows the spectra of idlers generated when the device is set at four different temperature values. The blue dashed curve corresponds to the case when the pumps are set at 1536.95 nm and 1538.15 nm separated by 1.2 nm at 78.2°C. Increasing the temperature by 4.8°C to 83.0°C shifts the phase matching wavelengths by 1.6 nm so that the idlers are also shifted by the same amount, shown by the red solid curve in Fig. 6(b). Similarly, when the temperature is set at 86.5°C, the idlers experience a total shift of 3.0 nm as depicted by the black dotted curve and for 89.0°C the idlers have shifted by 4.4 nm shown by the green dash-dotted curve in Fig. 6(b). Hence, tuning the temperature by ~10°C shifts the idlers by 4.4 nm to be positioned at WDM channels 12, 15 and 18. Employing temperature tuning, we observed no degradation in the response of PPLN in terms of idler efficiency. Using this device, an overall idler wavelength shift of less than 10 nm by selecting pumps at desired wavelengths attained via temperature tuning, is sufficient to cover up to 40 WDM (50 GHz spacing) channels for multiple idler broadcasting. The location of idlers can thus be varied by slightly tuning the input pump wavelengths within the device’s QPM bandwidth using temperature tuning. Based on these results, we can simply predict that the flexibility of broadcasting using the cSHG-SFG/DFG scheme to multiple channels can be extended to cover the entire C-band by tuning the temperature of the chirped multiple-QPM PPLN device.

6. Conclusion

In summary, we have shown for the first time, tunable wavelength broadcasting in a 10-mm long multiple-QPM PPLN. We successfully broadcast one signal into three idlers based on cascaded SHG-SFG/DFG in the novel PPLN device for which three SH-SF peaks were achieved. The mutual spacing of idlers and their position in the WDM grid was adjusted by tuning of the two pump wavelengths assisted by temperature adjustment of the PPLN. The temperature tunability of the multiple-QPM PPLN device assists in the choice of suitable pump wavelengths for tunable wavelength broadcasting by positioning the idlers at desired destination channels in WDM networks. Channel selective multiple broadcasting achieved by this scheme proves its crucial function in signal path routing enabling the effective usage of WDM bandwidth and flexible network construction.

Acknowledgments

Support from a Strategic Grant of NSERC (Natural Sciences and Engineering Research Council), Canada is acknowledged. R. Kashyap also acknowledges the support of the Canada Research Chairs Programs of the Government of Canada. M. Cha wants to thank the support of the National Research Foundation (NRF) Grant funded by the Ministry of Education, Science and Technology of Korea (2009-0074213).

References and Links

1. M. Gong, Y. Chen, F. Lu, and X. Chen, “All optical wavelength broadcast based on simultaneous Type I QPM broadband SFG and SHG in MgO:PPLN,” Opt. Lett. 35(16), 2672–2674 (2010). [CrossRef]   [PubMed]  

2. M. Ahlawat, A. Tehranchi, C. Q. Xu, and R. Kashyap, “Ultrabroadband flattop wavelength conversion based on cascaded sum frequency generation and difference frequency generation using pump detuning in quasi-phase-matched lithium niobate waveguides,” Appl. Opt. 50(25), E108–E111 (2011). [CrossRef]  

3. B. Chen, C.-Q. Xu, B. Zhou, Y. Nihei, and A. Harada, “All-optical variable-in variable-out wavelength conversions by using MgO:LiNbO3 quasiphase matched wavelength converters,” Jpn. J. Appl. Phys. 40, 3 (2001).

4. J. Shen, S. Yu, W. Gu, and J. Q. Yao, “Optimum design for 160-Gb/s all-optical time-domain demultiplexing based on cascaded second-order nonlinearities of SHG and DFG,” IEEE J. Quantum Electron. 45(6), 694–699 (2009). [CrossRef]  

5. W. Sohler, D. Buchter, L. Gui, H. Herrmann, H. Hu, R. Ludwig, R. Nouroozi, V. Quiring, R. Ricken, C. Schubert, and H. Suche, “Wavelength conversion and optical signal processing in PPLN waveguides,” in Communications and Photonics Conference and Exhibition (ACP), 2009 Asia, (2009), 1–2.

6. F. Lu, Y. Chen, J. Zhang, W. Lu, X. Chen, and Y. Xia, “Broadcast wavelength conversion based on cascaded χ(2) nonlinearity in MgO-doped periodically poled LiNbO3,” Electron. Lett. 43(25), 1446–1447 (2007). [CrossRef]  

7. C. Langrock, S. Kumar, J. E. McGeehan, A. E. Willner, and M. M. Fejer, “All-optical signal processing using χ(2) nonlinearities in guided-wave devices,” J. Lightwave Technol. 24(7), 2579–2592 (2006). [CrossRef]  

8. J. Wang and J. Sun, “40Gbit/s all-optical tunable format conversion in LiNbO3 waveguides based on cascaded SHG/DFG interactions,” in (SPIE, 2006), 634407–634407.

9. C. Q. Xu and B. Chen, “Cascaded wavelength conversions based on sum-frequency generation and difference-frequency generation,” Opt. Lett. 29(3), 292–294 (2004). [CrossRef]   [PubMed]  

10. A. Tehranchi and R. Kashyap, “Improved cascaded sum and difference frequency generation-based wavelength converters in low-loss quasi-phase-matched lithium niobate waveguides,” Appl. Opt. 48(31), G143–G147 (2009). [CrossRef]   [PubMed]  

11. A. Tehranchi, R. Morandotti, and R. Kashyap, “Efficient flattop ultra-wideband wavelength converters based on double-pass cascaded sum and difference frequency generation using engineered chirped gratings,” Opt. Express 19(23), 22528–22534 (2011). [CrossRef]   [PubMed]  

12. J. Zhang, Y. Chen, F. Lu, and X. Chen, “Flexible wavelength conversion via cascaded second order nonlinearity using broadband SHG in MgO-doped PPLN,” Opt. Express 16(10), 6957–6962 (2008). [CrossRef]   [PubMed]  

13. M. Asobe, O. Tadanaga, T. Umeki, T. Yanagawa, K. Magari, and H. Ishii, “Engineered quasi-phase matching device for unequally spaced multiple wavelength generation and its application to midinfrared gas sensing,” IEEE J. Quantum Electron. 46(4), 447–453 (2010). [CrossRef]  

14. M. H. Chou, K. R. Parameswaran, M. M. Fejer, and I. Brener, “Multiple-channel wavelength conversion by use of engineered quasi-phase-matching structures in LiNbO3 waveguides,” Opt. Lett. 24(16), 1157–1159 (1999). [CrossRef]   [PubMed]  

15. O. F. Yilmaz, S. R. Nuccio, S. Khaleghi, J. Y. Yang, L. Christen, and A. E. Willner, “Optical multiplexing of two 21.5 Gb/s DPSK signals into a single 43 Gb/s DQPSK channel with simultaneous 7-fold multicasting in a single PPLN waveguide,” in Optical Fiber Communication - incudes post deadline papers, (2009), 1–3.

16. M. Ahlawat, A. Tehranchi, K. Pandiyan, M. Cha, and R. Kashyap, “Tunable wavelength broadcasting in a PPLN with multiple QPM peaks,” in Nonlinear Photonics, (2012), JTu5A.37.

17. K. Pandiyan, Y. S. Kang, H. H. Lim, B. J. Kim, and M. Cha, “Nondestructive quality evaluation of periodically poled lithium niobate crystals by diffraction,” Opt. Express 17(20), 17862–17867 (2009). [CrossRef]   [PubMed]  

18. S. K. Pandiyan, Fabrication of periodically poled Lithium Niobate crystals for quasi-phase matching nonlinear optics and quality evaluation by diffraction, (Pusan National University, Busan, 2010).

19. D. H. Jundt, “Temperature-dependent Sellmeier equation for the index of refraction, ne, in congruent lithium niobate,” Opt. Lett. 22(20), 1553–1555 (1997). [CrossRef]   [PubMed]  

20. G. D. Boyd and D. A. Kleinman, “Parametric Interaction of Focused Gaussian Light Beams,” J. Appl. Phys. 39(8), 3597–3639 (1968). [CrossRef]  

21. W. P. Risk, T. R. Gosnell, and A. V. Nurmikko, Compact Blue-Green Lasers (Cambridge University Press, 2003).

22. K. J. Lee, S. Liu, K. Gallo, P. Petropoulos, and D. J. Richardson, “Analysis of acceptable spectral windows of quadratic cascaded nonlinear processes in a periodically poled lithium niobate waveguide,” Opt. Express 19(9), 8327–8335 (2011). [CrossRef]   [PubMed]  

References

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  1. M. Gong, Y. Chen, F. Lu, and X. Chen, “All optical wavelength broadcast based on simultaneous Type I QPM broadband SFG and SHG in MgO:PPLN,” Opt. Lett. 35(16), 2672–2674 (2010).
    [Crossref] [PubMed]
  2. M. Ahlawat, A. Tehranchi, C. Q. Xu, and R. Kashyap, “Ultrabroadband flattop wavelength conversion based on cascaded sum frequency generation and difference frequency generation using pump detuning in quasi-phase-matched lithium niobate waveguides,” Appl. Opt. 50(25), E108–E111 (2011).
    [Crossref]
  3. B. Chen, C.-Q. Xu, B. Zhou, Y. Nihei, and A. Harada, “All-optical variable-in variable-out wavelength conversions by using MgO:LiNbO3 quasiphase matched wavelength converters,” Jpn. J. Appl. Phys. 40, 3 (2001).
  4. J. Shen, S. Yu, W. Gu, and J. Q. Yao, “Optimum design for 160-Gb/s all-optical time-domain demultiplexing based on cascaded second-order nonlinearities of SHG and DFG,” IEEE J. Quantum Electron. 45(6), 694–699 (2009).
    [Crossref]
  5. W. Sohler, D. Buchter, L. Gui, H. Herrmann, H. Hu, R. Ludwig, R. Nouroozi, V. Quiring, R. Ricken, C. Schubert, and H. Suche, “Wavelength conversion and optical signal processing in PPLN waveguides,” in Communications and Photonics Conference and Exhibition (ACP), 2009 Asia, (2009), 1–2.
  6. F. Lu, Y. Chen, J. Zhang, W. Lu, X. Chen, and Y. Xia, “Broadcast wavelength conversion based on cascaded χ(2) nonlinearity in MgO-doped periodically poled LiNbO3,” Electron. Lett. 43(25), 1446–1447 (2007).
    [Crossref]
  7. C. Langrock, S. Kumar, J. E. McGeehan, A. E. Willner, and M. M. Fejer, “All-optical signal processing using χ(2) nonlinearities in guided-wave devices,” J. Lightwave Technol. 24(7), 2579–2592 (2006).
    [Crossref]
  8. J. Wang and J. Sun, “40Gbit/s all-optical tunable format conversion in LiNbO3 waveguides based on cascaded SHG/DFG interactions,” in (SPIE, 2006), 634407–634407.
  9. C. Q. Xu and B. Chen, “Cascaded wavelength conversions based on sum-frequency generation and difference-frequency generation,” Opt. Lett. 29(3), 292–294 (2004).
    [Crossref] [PubMed]
  10. A. Tehranchi and R. Kashyap, “Improved cascaded sum and difference frequency generation-based wavelength converters in low-loss quasi-phase-matched lithium niobate waveguides,” Appl. Opt. 48(31), G143–G147 (2009).
    [Crossref] [PubMed]
  11. A. Tehranchi, R. Morandotti, and R. Kashyap, “Efficient flattop ultra-wideband wavelength converters based on double-pass cascaded sum and difference frequency generation using engineered chirped gratings,” Opt. Express 19(23), 22528–22534 (2011).
    [Crossref] [PubMed]
  12. J. Zhang, Y. Chen, F. Lu, and X. Chen, “Flexible wavelength conversion via cascaded second order nonlinearity using broadband SHG in MgO-doped PPLN,” Opt. Express 16(10), 6957–6962 (2008).
    [Crossref] [PubMed]
  13. M. Asobe, O. Tadanaga, T. Umeki, T. Yanagawa, K. Magari, and H. Ishii, “Engineered quasi-phase matching device for unequally spaced multiple wavelength generation and its application to midinfrared gas sensing,” IEEE J. Quantum Electron. 46(4), 447–453 (2010).
    [Crossref]
  14. M. H. Chou, K. R. Parameswaran, M. M. Fejer, and I. Brener, “Multiple-channel wavelength conversion by use of engineered quasi-phase-matching structures in LiNbO3 waveguides,” Opt. Lett. 24(16), 1157–1159 (1999).
    [Crossref] [PubMed]
  15. O. F. Yilmaz, S. R. Nuccio, S. Khaleghi, J. Y. Yang, L. Christen, and A. E. Willner, “Optical multiplexing of two 21.5 Gb/s DPSK signals into a single 43 Gb/s DQPSK channel with simultaneous 7-fold multicasting in a single PPLN waveguide,” in Optical Fiber Communication - incudes post deadline papers, (2009), 1–3.
  16. M. Ahlawat, A. Tehranchi, K. Pandiyan, M. Cha, and R. Kashyap, “Tunable wavelength broadcasting in a PPLN with multiple QPM peaks,” in Nonlinear Photonics, (2012), JTu5A.37.
  17. K. Pandiyan, Y. S. Kang, H. H. Lim, B. J. Kim, and M. Cha, “Nondestructive quality evaluation of periodically poled lithium niobate crystals by diffraction,” Opt. Express 17(20), 17862–17867 (2009).
    [Crossref] [PubMed]
  18. S. K. Pandiyan, Fabrication of periodically poled Lithium Niobate crystals for quasi-phase matching nonlinear optics and quality evaluation by diffraction, (Pusan National University, Busan, 2010).
  19. D. H. Jundt, “Temperature-dependent Sellmeier equation for the index of refraction, ne, in congruent lithium niobate,” Opt. Lett. 22(20), 1553–1555 (1997).
    [Crossref] [PubMed]
  20. G. D. Boyd and D. A. Kleinman, “Parametric Interaction of Focused Gaussian Light Beams,” J. Appl. Phys. 39(8), 3597–3639 (1968).
    [Crossref]
  21. W. P. Risk, T. R. Gosnell, and A. V. Nurmikko, Compact Blue-Green Lasers (Cambridge University Press, 2003).
  22. K. J. Lee, S. Liu, K. Gallo, P. Petropoulos, and D. J. Richardson, “Analysis of acceptable spectral windows of quadratic cascaded nonlinear processes in a periodically poled lithium niobate waveguide,” Opt. Express 19(9), 8327–8335 (2011).
    [Crossref] [PubMed]

2011 (3)

2010 (2)

M. Asobe, O. Tadanaga, T. Umeki, T. Yanagawa, K. Magari, and H. Ishii, “Engineered quasi-phase matching device for unequally spaced multiple wavelength generation and its application to midinfrared gas sensing,” IEEE J. Quantum Electron. 46(4), 447–453 (2010).
[Crossref]

M. Gong, Y. Chen, F. Lu, and X. Chen, “All optical wavelength broadcast based on simultaneous Type I QPM broadband SFG and SHG in MgO:PPLN,” Opt. Lett. 35(16), 2672–2674 (2010).
[Crossref] [PubMed]

2009 (3)

2008 (1)

2007 (1)

F. Lu, Y. Chen, J. Zhang, W. Lu, X. Chen, and Y. Xia, “Broadcast wavelength conversion based on cascaded χ(2) nonlinearity in MgO-doped periodically poled LiNbO3,” Electron. Lett. 43(25), 1446–1447 (2007).
[Crossref]

2006 (1)

2004 (1)

2001 (1)

B. Chen, C.-Q. Xu, B. Zhou, Y. Nihei, and A. Harada, “All-optical variable-in variable-out wavelength conversions by using MgO:LiNbO3 quasiphase matched wavelength converters,” Jpn. J. Appl. Phys. 40, 3 (2001).

1999 (1)

1997 (1)

1968 (1)

G. D. Boyd and D. A. Kleinman, “Parametric Interaction of Focused Gaussian Light Beams,” J. Appl. Phys. 39(8), 3597–3639 (1968).
[Crossref]

Ahlawat, M.

Asobe, M.

M. Asobe, O. Tadanaga, T. Umeki, T. Yanagawa, K. Magari, and H. Ishii, “Engineered quasi-phase matching device for unequally spaced multiple wavelength generation and its application to midinfrared gas sensing,” IEEE J. Quantum Electron. 46(4), 447–453 (2010).
[Crossref]

Boyd, G. D.

G. D. Boyd and D. A. Kleinman, “Parametric Interaction of Focused Gaussian Light Beams,” J. Appl. Phys. 39(8), 3597–3639 (1968).
[Crossref]

Brener, I.

Cha, M.

Chen, B.

C. Q. Xu and B. Chen, “Cascaded wavelength conversions based on sum-frequency generation and difference-frequency generation,” Opt. Lett. 29(3), 292–294 (2004).
[Crossref] [PubMed]

B. Chen, C.-Q. Xu, B. Zhou, Y. Nihei, and A. Harada, “All-optical variable-in variable-out wavelength conversions by using MgO:LiNbO3 quasiphase matched wavelength converters,” Jpn. J. Appl. Phys. 40, 3 (2001).

Chen, X.

Chen, Y.

Chou, M. H.

Fejer, M. M.

Gallo, K.

Gong, M.

Gu, W.

J. Shen, S. Yu, W. Gu, and J. Q. Yao, “Optimum design for 160-Gb/s all-optical time-domain demultiplexing based on cascaded second-order nonlinearities of SHG and DFG,” IEEE J. Quantum Electron. 45(6), 694–699 (2009).
[Crossref]

Harada, A.

B. Chen, C.-Q. Xu, B. Zhou, Y. Nihei, and A. Harada, “All-optical variable-in variable-out wavelength conversions by using MgO:LiNbO3 quasiphase matched wavelength converters,” Jpn. J. Appl. Phys. 40, 3 (2001).

Ishii, H.

M. Asobe, O. Tadanaga, T. Umeki, T. Yanagawa, K. Magari, and H. Ishii, “Engineered quasi-phase matching device for unequally spaced multiple wavelength generation and its application to midinfrared gas sensing,” IEEE J. Quantum Electron. 46(4), 447–453 (2010).
[Crossref]

Jundt, D. H.

Kang, Y. S.

Kashyap, R.

Kim, B. J.

Kleinman, D. A.

G. D. Boyd and D. A. Kleinman, “Parametric Interaction of Focused Gaussian Light Beams,” J. Appl. Phys. 39(8), 3597–3639 (1968).
[Crossref]

Kumar, S.

Langrock, C.

Lee, K. J.

Lim, H. H.

Liu, S.

Lu, F.

Lu, W.

F. Lu, Y. Chen, J. Zhang, W. Lu, X. Chen, and Y. Xia, “Broadcast wavelength conversion based on cascaded χ(2) nonlinearity in MgO-doped periodically poled LiNbO3,” Electron. Lett. 43(25), 1446–1447 (2007).
[Crossref]

Magari, K.

M. Asobe, O. Tadanaga, T. Umeki, T. Yanagawa, K. Magari, and H. Ishii, “Engineered quasi-phase matching device for unequally spaced multiple wavelength generation and its application to midinfrared gas sensing,” IEEE J. Quantum Electron. 46(4), 447–453 (2010).
[Crossref]

McGeehan, J. E.

Morandotti, R.

Nihei, Y.

B. Chen, C.-Q. Xu, B. Zhou, Y. Nihei, and A. Harada, “All-optical variable-in variable-out wavelength conversions by using MgO:LiNbO3 quasiphase matched wavelength converters,” Jpn. J. Appl. Phys. 40, 3 (2001).

Pandiyan, K.

Parameswaran, K. R.

Petropoulos, P.

Richardson, D. J.

Shen, J.

J. Shen, S. Yu, W. Gu, and J. Q. Yao, “Optimum design for 160-Gb/s all-optical time-domain demultiplexing based on cascaded second-order nonlinearities of SHG and DFG,” IEEE J. Quantum Electron. 45(6), 694–699 (2009).
[Crossref]

Tadanaga, O.

M. Asobe, O. Tadanaga, T. Umeki, T. Yanagawa, K. Magari, and H. Ishii, “Engineered quasi-phase matching device for unequally spaced multiple wavelength generation and its application to midinfrared gas sensing,” IEEE J. Quantum Electron. 46(4), 447–453 (2010).
[Crossref]

Tehranchi, A.

Umeki, T.

M. Asobe, O. Tadanaga, T. Umeki, T. Yanagawa, K. Magari, and H. Ishii, “Engineered quasi-phase matching device for unequally spaced multiple wavelength generation and its application to midinfrared gas sensing,” IEEE J. Quantum Electron. 46(4), 447–453 (2010).
[Crossref]

Willner, A. E.

Xia, Y.

F. Lu, Y. Chen, J. Zhang, W. Lu, X. Chen, and Y. Xia, “Broadcast wavelength conversion based on cascaded χ(2) nonlinearity in MgO-doped periodically poled LiNbO3,” Electron. Lett. 43(25), 1446–1447 (2007).
[Crossref]

Xu, C. Q.

Xu, C.-Q.

B. Chen, C.-Q. Xu, B. Zhou, Y. Nihei, and A. Harada, “All-optical variable-in variable-out wavelength conversions by using MgO:LiNbO3 quasiphase matched wavelength converters,” Jpn. J. Appl. Phys. 40, 3 (2001).

Yanagawa, T.

M. Asobe, O. Tadanaga, T. Umeki, T. Yanagawa, K. Magari, and H. Ishii, “Engineered quasi-phase matching device for unequally spaced multiple wavelength generation and its application to midinfrared gas sensing,” IEEE J. Quantum Electron. 46(4), 447–453 (2010).
[Crossref]

Yao, J. Q.

J. Shen, S. Yu, W. Gu, and J. Q. Yao, “Optimum design for 160-Gb/s all-optical time-domain demultiplexing based on cascaded second-order nonlinearities of SHG and DFG,” IEEE J. Quantum Electron. 45(6), 694–699 (2009).
[Crossref]

Yu, S.

J. Shen, S. Yu, W. Gu, and J. Q. Yao, “Optimum design for 160-Gb/s all-optical time-domain demultiplexing based on cascaded second-order nonlinearities of SHG and DFG,” IEEE J. Quantum Electron. 45(6), 694–699 (2009).
[Crossref]

Zhang, J.

J. Zhang, Y. Chen, F. Lu, and X. Chen, “Flexible wavelength conversion via cascaded second order nonlinearity using broadband SHG in MgO-doped PPLN,” Opt. Express 16(10), 6957–6962 (2008).
[Crossref] [PubMed]

F. Lu, Y. Chen, J. Zhang, W. Lu, X. Chen, and Y. Xia, “Broadcast wavelength conversion based on cascaded χ(2) nonlinearity in MgO-doped periodically poled LiNbO3,” Electron. Lett. 43(25), 1446–1447 (2007).
[Crossref]

Zhou, B.

B. Chen, C.-Q. Xu, B. Zhou, Y. Nihei, and A. Harada, “All-optical variable-in variable-out wavelength conversions by using MgO:LiNbO3 quasiphase matched wavelength converters,” Jpn. J. Appl. Phys. 40, 3 (2001).

Appl. Opt. (2)

Electron. Lett. (1)

F. Lu, Y. Chen, J. Zhang, W. Lu, X. Chen, and Y. Xia, “Broadcast wavelength conversion based on cascaded χ(2) nonlinearity in MgO-doped periodically poled LiNbO3,” Electron. Lett. 43(25), 1446–1447 (2007).
[Crossref]

IEEE J. Quantum Electron. (2)

J. Shen, S. Yu, W. Gu, and J. Q. Yao, “Optimum design for 160-Gb/s all-optical time-domain demultiplexing based on cascaded second-order nonlinearities of SHG and DFG,” IEEE J. Quantum Electron. 45(6), 694–699 (2009).
[Crossref]

M. Asobe, O. Tadanaga, T. Umeki, T. Yanagawa, K. Magari, and H. Ishii, “Engineered quasi-phase matching device for unequally spaced multiple wavelength generation and its application to midinfrared gas sensing,” IEEE J. Quantum Electron. 46(4), 447–453 (2010).
[Crossref]

J. Appl. Phys. (1)

G. D. Boyd and D. A. Kleinman, “Parametric Interaction of Focused Gaussian Light Beams,” J. Appl. Phys. 39(8), 3597–3639 (1968).
[Crossref]

J. Lightwave Technol. (1)

Jpn. J. Appl. Phys. (1)

B. Chen, C.-Q. Xu, B. Zhou, Y. Nihei, and A. Harada, “All-optical variable-in variable-out wavelength conversions by using MgO:LiNbO3 quasiphase matched wavelength converters,” Jpn. J. Appl. Phys. 40, 3 (2001).

Opt. Express (4)

Opt. Lett. (4)

Other (6)

J. Wang and J. Sun, “40Gbit/s all-optical tunable format conversion in LiNbO3 waveguides based on cascaded SHG/DFG interactions,” in (SPIE, 2006), 634407–634407.

W. Sohler, D. Buchter, L. Gui, H. Herrmann, H. Hu, R. Ludwig, R. Nouroozi, V. Quiring, R. Ricken, C. Schubert, and H. Suche, “Wavelength conversion and optical signal processing in PPLN waveguides,” in Communications and Photonics Conference and Exhibition (ACP), 2009 Asia, (2009), 1–2.

O. F. Yilmaz, S. R. Nuccio, S. Khaleghi, J. Y. Yang, L. Christen, and A. E. Willner, “Optical multiplexing of two 21.5 Gb/s DPSK signals into a single 43 Gb/s DQPSK channel with simultaneous 7-fold multicasting in a single PPLN waveguide,” in Optical Fiber Communication - incudes post deadline papers, (2009), 1–3.

M. Ahlawat, A. Tehranchi, K. Pandiyan, M. Cha, and R. Kashyap, “Tunable wavelength broadcasting in a PPLN with multiple QPM peaks,” in Nonlinear Photonics, (2012), JTu5A.37.

S. K. Pandiyan, Fabrication of periodically poled Lithium Niobate crystals for quasi-phase matching nonlinear optics and quality evaluation by diffraction, (Pusan National University, Busan, 2010).

W. P. Risk, T. R. Gosnell, and A. V. Nurmikko, Compact Blue-Green Lasers (Cambridge University Press, 2003).

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Figures (6)

Fig. 1
Fig. 1

Experimental setup for cSFG/DFG with two pumps and a signal, PC: Polarization Controller, OSA: Optical Spectrum Analyzer. For SFG, just the two pump wavelengths are coupled into the setup. PPLN with a central aperiodic domain having width equal to size of the device period is shown.

Fig. 2
Fig. 2

(a) SH power vs. pump wavelength, theoretical (solid black) and experimentally observed (dotted, red) plots for the 2-peak QPM structure shown. (b) Spectra of multiple SHG-SFG for the different cases of 2 SH and 1 SF output (blue dashed); 1SH and 1SF (dash-dotted red curve); 1SH peak (green solid trace)

Fig. 3
Fig. 3

(a) Spectrum of multiple SHG-SFG showing equalized peak powers achieved by pump detuning, mutual spacing of the peaks is 0.55 nm. (b) Spectra of three SH-SF peaks showing 0.6 nm peak-wavelength shift over a 3°C temperature difference when the two pump wavelengths were simultaneously shifted from 1537.3 nm and 1538.5 nm to 1538.5 nm and 1539.7 nm.

Fig. 4
Fig. 4

(a) Scheme for tunable broadcasting of a signal into three idlers by detuning of the pump wavelengths (b) Spectral variation of idler spacing with detuning of both pump wavelengths.

Fig. 5
Fig. 5

(a) Scheme for tunable broadcasting of a signal into three idlers by detuning of pump wavelength. (b) Spectral variation of idler spacing with pump wavelengths separation by tuning just one pump wavelength.

Fig. 6
Fig. 6

(a) Scheme for tunable broadcasting of a signal into three idlers by temperature-assisted pump-wavelength tuning. (b) Tunable triple-idler broadcasting of a signal at 1545.27 nm with shifting the two-pump wavelengths at 1536.95 nm and 1538.15 nm by + 1.6 nm, + 3 nm and + 4.4 nm and simultaneous temperature tuning from 78.2°C by + 4.8°C, + 8.3°C and + 10.8°C.

Equations (4)

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

κ(x)= d eff sin( 2πx Λ )[ rect( xl/4 l/2 )rect( x3l/4 l/2 ) ]
A 2 (q)=i A 1 2 l d eff e iπl( q± 1 Λ ) si n 2 ( π 2 l( q± 1 Λ ) ) π 2 l( q± 1 Λ )
n SF ω SF /c n 1 ω p1 /c n 2 ω p2 /c=2π/Λ,
n SF ω SF /c n s ω s /c n c ω c /c=2π/Λ,

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