Abstract

A Mach-Zehnder interferometer (MZI) composed by a pair of long period gratings (LPGs) fabricated in silica microfiber for sensing applications is demonstrated. Each LPG is fabricated with a pulsed CO2 laser by creating six periodical deformations along fiber length with only one scanning cycle. The length of the MZI can reach as short as 8.84 mm when the diameter of the microfiber is 9.5 μm. Compared with the ones fabricated in single-mode fibers, the present MZI is much shorter owing to the large effective-index difference between the fundamental and higher order modes. The microfiber MZI exhibits a sensitivity to surrounding refractive index (RI) of 2225 nm per refractive index unit and the temperature sensitivity of only 11.7 pm/°C. Theoretical analysis suggests that the performances of the MZI sensor can be improved by using thinner microfibers with a diameter down to 3.5 μm: The sensitivity can be greatly enhanced due to the stronger evanescent-field interaction and reduced dispersion factor; the transmission dips become narrower which benefits high-resolution measurement; the thinner fiber also allows further reduction in device length. The present device has great potential in biochemical and medical sensing due to the advantages including easy fabrication, excellent compactness and high sensitivity.

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    [CrossRef]
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    [CrossRef]
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    [CrossRef]
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    [CrossRef]
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    [CrossRef] [PubMed]

2011

2010

2009

2008

L. V. Nguyen, D. Hwang, S. Moon, D. S. Moon, and Y. Chung, “High temperature fiber sensor with high sensitivity based on core diameter mismatch,” Opt. Express16(15), 11369–11375 (2008).
[CrossRef] [PubMed]

Z. Tian, S. S.-H. Yam, J. Barnes, W. Bock, P. Greig, J. M. Fraser, H.-P. Loock, and R. D. Oleschuk, “Refractive index sensing with Mach–Zehnder interferometer based on concatenating two single-mode fiber tapers,” IEEE Photon. Technol. Lett.20(8), 626–628 (2008).
[CrossRef]

Y. Li and L. Tong, “Mach-Zehnder interferometers assembled with optical microfibers or nanofibers,” Opt. Lett.33(4), 303–305 (2008).
[CrossRef] [PubMed]

2005

J. F. Ding, A. P. Zhang, L. Y. Shao, J. H. Yan, and S. He, “Fiber-taper seeded long-period grating pair as a highly sensitive refractive-index sensor,” IEEE Photon. Technol. Lett.17(6), 1247–1249 (2005).
[CrossRef]

2004

2003

L. M. Tong, R. R. Gattass, J. B. Ashcom, S. L. He, J. Y. Lou, M. Y. Shen, I. Maxwell, and E. Mazur, “Subwavelength-diameter silica wires for low-loss optical wave guiding,” Nature426(6968), 816–819 (2003).
[CrossRef] [PubMed]

2002

1999

B. H. Lee and J. Nishii, “Dependence of fringe spacing on the grating separation in a long-period fiber grating pair,” Appl. Opt.38(16), 3450–3459 (1999).
[CrossRef] [PubMed]

Y. Liu, J. A. R. Williams, L. Zhang, and I. Bennion, “Phase shifted and cascaded long-period fiber gratings,” Opt. Commun.164(1-3), 27–31 (1999).
[CrossRef]

D. B. Stegall and T. Erdogan, “Leaky cladding mode propagation in long-period fibre grating devices,” IEEE Photon. Technol. Lett.11(3), 343–345 (1999).
[CrossRef]

1998

Allsop, T.

T. Allsop, R. Reeves, D. J. Webb, I. Bennion, and R. Neal, “A high sensitivity refractometer based upon a long period grating Mach–Zehnder interferometer,” Rev. Sci. Instrum.73(4), 1702–1705 (2002).
[CrossRef]

Ashcom, J. B.

L. M. Tong, R. R. Gattass, J. B. Ashcom, S. L. He, J. Y. Lou, M. Y. Shen, I. Maxwell, and E. Mazur, “Subwavelength-diameter silica wires for low-loss optical wave guiding,” Nature426(6968), 816–819 (2003).
[CrossRef] [PubMed]

Barnes, J.

Z. Tian, S. S.-H. Yam, J. Barnes, W. Bock, P. Greig, J. M. Fraser, H.-P. Loock, and R. D. Oleschuk, “Refractive index sensing with Mach–Zehnder interferometer based on concatenating two single-mode fiber tapers,” IEEE Photon. Technol. Lett.20(8), 626–628 (2008).
[CrossRef]

Bennion, I.

T. Allsop, R. Reeves, D. J. Webb, I. Bennion, and R. Neal, “A high sensitivity refractometer based upon a long period grating Mach–Zehnder interferometer,” Rev. Sci. Instrum.73(4), 1702–1705 (2002).
[CrossRef]

X. Shu, L. Zhang, and I. Bennion, “Sensitivity characteristics of long-period fiber gratings,” J. Lightwave Technol.20(2), 255–266 (2002).
[CrossRef]

Y. Liu, J. A. R. Williams, L. Zhang, and I. Bennion, “Phase shifted and cascaded long-period fiber gratings,” Opt. Commun.164(1-3), 27–31 (1999).
[CrossRef]

Bock, W.

Z. Tian, S. S.-H. Yam, J. Barnes, W. Bock, P. Greig, J. M. Fraser, H.-P. Loock, and R. D. Oleschuk, “Refractive index sensing with Mach–Zehnder interferometer based on concatenating two single-mode fiber tapers,” IEEE Photon. Technol. Lett.20(8), 626–628 (2008).
[CrossRef]

Brambilla, G.

Chang, Y. L.

Chen, Q.

P. Lu, L. Men, K. Sooley, and Q. Chen, “Tapered fiber Mach–Zehnder interferometer for simultaneous measurement of refractive index and temperature,” Appl. Phys. Lett.94(13), 131110 (2009).
[CrossRef]

Chung, Y.

Ding, J. F.

J. F. Ding, A. P. Zhang, L. Y. Shao, J. H. Yan, and S. He, “Fiber-taper seeded long-period grating pair as a highly sensitive refractive-index sensor,” IEEE Photon. Technol. Lett.17(6), 1247–1249 (2005).
[CrossRef]

Erdogan, T.

D. B. Stegall and T. Erdogan, “Leaky cladding mode propagation in long-period fibre grating devices,” IEEE Photon. Technol. Lett.11(3), 343–345 (1999).
[CrossRef]

Feng, X.

Fraser, J. M.

Z. Tian, S. S.-H. Yam, J. Barnes, W. Bock, P. Greig, J. M. Fraser, H.-P. Loock, and R. D. Oleschuk, “Refractive index sensing with Mach–Zehnder interferometer based on concatenating two single-mode fiber tapers,” IEEE Photon. Technol. Lett.20(8), 626–628 (2008).
[CrossRef]

Gao, S.

Gattass, R. R.

L. M. Tong, R. R. Gattass, J. B. Ashcom, S. L. He, J. Y. Lou, M. Y. Shen, I. Maxwell, and E. Mazur, “Subwavelength-diameter silica wires for low-loss optical wave guiding,” Nature426(6968), 816–819 (2003).
[CrossRef] [PubMed]

Greig, P.

Z. Tian, S. S.-H. Yam, J. Barnes, W. Bock, P. Greig, J. M. Fraser, H.-P. Loock, and R. D. Oleschuk, “Refractive index sensing with Mach–Zehnder interferometer based on concatenating two single-mode fiber tapers,” IEEE Photon. Technol. Lett.20(8), 626–628 (2008).
[CrossRef]

Gu, X. J.

Guan, B. O.

He, S.

J. F. Ding, A. P. Zhang, L. Y. Shao, J. H. Yan, and S. He, “Fiber-taper seeded long-period grating pair as a highly sensitive refractive-index sensor,” IEEE Photon. Technol. Lett.17(6), 1247–1249 (2005).
[CrossRef]

He, S. L.

L. M. Tong, R. R. Gattass, J. B. Ashcom, S. L. He, J. Y. Lou, M. Y. Shen, I. Maxwell, and E. Mazur, “Subwavelength-diameter silica wires for low-loss optical wave guiding,” Nature426(6968), 816–819 (2003).
[CrossRef] [PubMed]

Horak, P.

Hwang, D.

Jang, H. S.

Jin, L.

Jin, W.

Ju, J.

Jung, Y.

Kim, J. C.

Kim, Y. J.

Koizumi, F.

Koukharenko, E.

Lee, B. H.

Lee, K. S.

Li, J.

Li, Y.

Lim, J. H.

Liu, Y.

Y. Liu, J. A. R. Williams, L. Zhang, and I. Bennion, “Phase shifted and cascaded long-period fiber gratings,” Opt. Commun.164(1-3), 27–31 (1999).
[CrossRef]

Loock, H.-P.

Z. Tian, S. S.-H. Yam, J. Barnes, W. Bock, P. Greig, J. M. Fraser, H.-P. Loock, and R. D. Oleschuk, “Refractive index sensing with Mach–Zehnder interferometer based on concatenating two single-mode fiber tapers,” IEEE Photon. Technol. Lett.20(8), 626–628 (2008).
[CrossRef]

Lou, J. Y.

L. M. Tong, R. R. Gattass, J. B. Ashcom, S. L. He, J. Y. Lou, M. Y. Shen, I. Maxwell, and E. Mazur, “Subwavelength-diameter silica wires for low-loss optical wave guiding,” Nature426(6968), 816–819 (2003).
[CrossRef] [PubMed]

Lu, P.

P. Lu, L. Men, K. Sooley, and Q. Chen, “Tapered fiber Mach–Zehnder interferometer for simultaneous measurement of refractive index and temperature,” Appl. Phys. Lett.94(13), 131110 (2009).
[CrossRef]

Maxwell, I.

L. M. Tong, R. R. Gattass, J. B. Ashcom, S. L. He, J. Y. Lou, M. Y. Shen, I. Maxwell, and E. Mazur, “Subwavelength-diameter silica wires for low-loss optical wave guiding,” Nature426(6968), 816–819 (2003).
[CrossRef] [PubMed]

Mazur, E.

L. M. Tong, R. R. Gattass, J. B. Ashcom, S. L. He, J. Y. Lou, M. Y. Shen, I. Maxwell, and E. Mazur, “Subwavelength-diameter silica wires for low-loss optical wave guiding,” Nature426(6968), 816–819 (2003).
[CrossRef] [PubMed]

Men, L.

P. Lu, L. Men, K. Sooley, and Q. Chen, “Tapered fiber Mach–Zehnder interferometer for simultaneous measurement of refractive index and temperature,” Appl. Phys. Lett.94(13), 131110 (2009).
[CrossRef]

Moon, D. S.

Moon, S.

Murugan, G. S.

Neal, R.

T. Allsop, R. Reeves, D. J. Webb, I. Bennion, and R. Neal, “A high sensitivity refractometer based upon a long period grating Mach–Zehnder interferometer,” Rev. Sci. Instrum.73(4), 1702–1705 (2002).
[CrossRef]

Nguyen, L. V.

Nishii, J.

Oleschuk, R. D.

Z. Tian, S. S.-H. Yam, J. Barnes, W. Bock, P. Greig, J. M. Fraser, H.-P. Loock, and R. D. Oleschuk, “Refractive index sensing with Mach–Zehnder interferometer based on concatenating two single-mode fiber tapers,” IEEE Photon. Technol. Lett.20(8), 626–628 (2008).
[CrossRef]

Paek, U. C.

Quan, Z.

Ran, Y.

Reeves, R.

T. Allsop, R. Reeves, D. J. Webb, I. Bennion, and R. Neal, “A high sensitivity refractometer based upon a long period grating Mach–Zehnder interferometer,” Rev. Sci. Instrum.73(4), 1702–1705 (2002).
[CrossRef]

Richardson, D. J.

Sessions, N. P.

Shao, L. Y.

J. F. Ding, A. P. Zhang, L. Y. Shao, J. H. Yan, and S. He, “Fiber-taper seeded long-period grating pair as a highly sensitive refractive-index sensor,” IEEE Photon. Technol. Lett.17(6), 1247–1249 (2005).
[CrossRef]

Shen, M. Y.

L. M. Tong, R. R. Gattass, J. B. Ashcom, S. L. He, J. Y. Lou, M. Y. Shen, I. Maxwell, and E. Mazur, “Subwavelength-diameter silica wires for low-loss optical wave guiding,” Nature426(6968), 816–819 (2003).
[CrossRef] [PubMed]

Shu, X.

Sooley, K.

P. Lu, L. Men, K. Sooley, and Q. Chen, “Tapered fiber Mach–Zehnder interferometer for simultaneous measurement of refractive index and temperature,” Appl. Phys. Lett.94(13), 131110 (2009).
[CrossRef]

Stegall, D. B.

D. B. Stegall and T. Erdogan, “Leaky cladding mode propagation in long-period fibre grating devices,” IEEE Photon. Technol. Lett.11(3), 343–345 (1999).
[CrossRef]

Sun, L. P.

Tian, Z.

Z. Tian, S. S.-H. Yam, J. Barnes, W. Bock, P. Greig, J. M. Fraser, H.-P. Loock, and R. D. Oleschuk, “Refractive index sensing with Mach–Zehnder interferometer based on concatenating two single-mode fiber tapers,” IEEE Photon. Technol. Lett.20(8), 626–628 (2008).
[CrossRef]

Tong, L.

Tong, L. M.

L. M. Tong, R. R. Gattass, J. B. Ashcom, S. L. He, J. Y. Lou, M. Y. Shen, I. Maxwell, and E. Mazur, “Subwavelength-diameter silica wires for low-loss optical wave guiding,” Nature426(6968), 816–819 (2003).
[CrossRef] [PubMed]

Wang, Y.

Webb, D. J.

T. Allsop, R. Reeves, D. J. Webb, I. Bennion, and R. Neal, “A high sensitivity refractometer based upon a long period grating Mach–Zehnder interferometer,” Rev. Sci. Instrum.73(4), 1702–1705 (2002).
[CrossRef]

Wilkinson, J. S.

Williams, J. A. R.

Y. Liu, J. A. R. Williams, L. Zhang, and I. Bennion, “Phase shifted and cascaded long-period fiber gratings,” Opt. Commun.164(1-3), 27–31 (1999).
[CrossRef]

Xu, F.

Xuan, H.

Yam, S. S.-H.

Z. Tian, S. S.-H. Yam, J. Barnes, W. Bock, P. Greig, J. M. Fraser, H.-P. Loock, and R. D. Oleschuk, “Refractive index sensing with Mach–Zehnder interferometer based on concatenating two single-mode fiber tapers,” IEEE Photon. Technol. Lett.20(8), 626–628 (2008).
[CrossRef]

Yan, J. H.

J. F. Ding, A. P. Zhang, L. Y. Shao, J. H. Yan, and S. He, “Fiber-taper seeded long-period grating pair as a highly sensitive refractive-index sensor,” IEEE Photon. Technol. Lett.17(6), 1247–1249 (2005).
[CrossRef]

Zhang, A. P.

J. F. Ding, A. P. Zhang, L. Y. Shao, J. H. Yan, and S. He, “Fiber-taper seeded long-period grating pair as a highly sensitive refractive-index sensor,” IEEE Photon. Technol. Lett.17(6), 1247–1249 (2005).
[CrossRef]

Zhang, L.

X. Shu, L. Zhang, and I. Bennion, “Sensitivity characteristics of long-period fiber gratings,” J. Lightwave Technol.20(2), 255–266 (2002).
[CrossRef]

Y. Liu, J. A. R. Williams, L. Zhang, and I. Bennion, “Phase shifted and cascaded long-period fiber gratings,” Opt. Commun.164(1-3), 27–31 (1999).
[CrossRef]

Zhang, M.

Adv. Opt. Photon.

Appl. Opt.

Appl. Phys. Lett.

P. Lu, L. Men, K. Sooley, and Q. Chen, “Tapered fiber Mach–Zehnder interferometer for simultaneous measurement of refractive index and temperature,” Appl. Phys. Lett.94(13), 131110 (2009).
[CrossRef]

IEEE Photon. Technol. Lett.

D. B. Stegall and T. Erdogan, “Leaky cladding mode propagation in long-period fibre grating devices,” IEEE Photon. Technol. Lett.11(3), 343–345 (1999).
[CrossRef]

Z. Tian, S. S.-H. Yam, J. Barnes, W. Bock, P. Greig, J. M. Fraser, H.-P. Loock, and R. D. Oleschuk, “Refractive index sensing with Mach–Zehnder interferometer based on concatenating two single-mode fiber tapers,” IEEE Photon. Technol. Lett.20(8), 626–628 (2008).
[CrossRef]

J. F. Ding, A. P. Zhang, L. Y. Shao, J. H. Yan, and S. He, “Fiber-taper seeded long-period grating pair as a highly sensitive refractive-index sensor,” IEEE Photon. Technol. Lett.17(6), 1247–1249 (2005).
[CrossRef]

J. Lightwave Technol.

J. Opt.

G. Brambilla, “Optical fibre nanowires and microwires: a review,” J. Opt.12(4), 1–19 (2010).
[CrossRef]

Nature

L. M. Tong, R. R. Gattass, J. B. Ashcom, S. L. He, J. Y. Lou, M. Y. Shen, I. Maxwell, and E. Mazur, “Subwavelength-diameter silica wires for low-loss optical wave guiding,” Nature426(6968), 816–819 (2003).
[CrossRef] [PubMed]

Opt. Commun.

Y. Liu, J. A. R. Williams, L. Zhang, and I. Bennion, “Phase shifted and cascaded long-period fiber gratings,” Opt. Commun.164(1-3), 27–31 (1999).
[CrossRef]

Opt. Express

Opt. Lett.

Rev. Sci. Instrum.

T. Allsop, R. Reeves, D. J. Webb, I. Bennion, and R. Neal, “A high sensitivity refractometer based upon a long period grating Mach–Zehnder interferometer,” Rev. Sci. Instrum.73(4), 1702–1705 (2002).
[CrossRef]

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Figures (7)

Fig. 1
Fig. 1

(a) Schematic setup for the MZI fabrication. BBS: Broadband source; OSA: Optical spectrum analyzer. (b) Microscopic image of a single deformation on the microfiber created by the CO2 laser. (c) Microscopic image of periodical deformations on a microfiber MZI.

Fig. 2
Fig. 2

(a) Measured transmission spectra of a single LPG with six deformations and the microfiber MZI in air. (b) Calculated phase-matching curves for couplings between the fundamental HE11 mode and HE31/EH11 modes. The calculation is performed for unperturbed microfibers. (c) Demonstration of the evolution of energy profiles for the EH11 and HE31 modes when a transverse asymmetric index modification is introduced. The arrows represent electric fields.

Fig. 3
Fig. 3

(a) Measured transmission spectrum of the MZI in the air at around 1050 nm; (b) Calculated transmission spectrum to approximate the measured result.

Fig. 4
Fig. 4

Measured and calculated wavelength shifts of four selected dips as a function of external refractive index. Circles: Measured results; Curves: Linear fits.

Fig. 5
Fig. 5

(a) Measured evolution of the transmission spectrum of a single dip with temperature change in air. (b) Measured and calculated dip wavelength shift as a function of temperature in air. Dots: Measured result; Curve: fitting result.

Fig. 6
Fig. 6

Calculated index differences Δn (a), dispersion factors Γ (b), RI sensitivities (c) and dip wavelength spacings S (d) as a function of wavelength for different fiber diameters.

Fig. 7
Fig. 7

Zero dispersion factor Γ = 0 can be obtained at the tangency point of the index difference curve. Red curve: The index difference curve; Black solid curve: Tangent curve Δn = qλ.

Equations (9)

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

λ LPG = Δn ¯ Λ
C ij (z)= 1 4 A { h j × e l z e j × h l z } · z dA
[ t r ]= M 2 M p M 1 [ 1 0 ]
T= | exp(iΔφ) t 1 t 2 + r 1 r 2 | 2
dλ d n ext =λ 1 Γ ( 1 Δn dΔn d n ext )
dλ dT =λ 1 Γ (α+ β si Δn dΔn dnsi )
(k+ 1 2 )λ=ΔnL
dλ dk = 1 L λ 2 ΔnΓ
S=| 1 L λ 2 ΔnΓ |

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