[1] Mao X, Huang J B, Gu H C. Demodulation technology of distributed feedback fiber laser sensor based on 3×3 coupler[J]. Chinese Journal of Luminescence, 38, 395-401(2017).

[2] Chen F F, Jiang Y, Jiang L. 3×3 coupler based interferometric magnetic field sensor using a TbDyFe rod[J]. Applied Optics, 54, 2085-2090(2015).

[3] Qi B, Winder D E, Liu Y. Quadrature phase-shifted optical demodulator for low-coherence fiber-optic Fabry-Perot interferometric sensors[J]. Optics Express, 27, 7319-7329(2019).

[4] Liu L, Lu P, Liao H et al. Fiber-optic Michelson interferometric acoustic sensor based on a PP/PET diaphragm[J]. IEEE Sensors Journal, 16, 3054-3058(2016).

[5] Jing S Q, Huang L, Dong W H et al. Positive and negative feedback judgment and high-frequency vibration detection by interferometer based on 3×3 coupler[J]. Acta Optica Sinica, 39, 0712001(2019).

[6] He J, Xiao H, Feng L et al. Analysis of phase characteristics of fiber Michelson interferometer based on a 3×3 coupler[J]. Acta Optica Sinica, 28, 1867-1873(2008).

[7] Todd M D, Seaver M, Bucholtz F. Improved, operationally-passive interferometric demodulation method using 3×3 coupler[J]. Electronics Letters, 38, 784-786(2002).

[8] Liu T T, Cui J, Chen D S et al. A new demodulation technique for optical fiber interferometric sensors with [3×3] directional couplers[J]. Chinese Optics Letters, 6, 12-15(2008).

[9] Fan P J, Yan W, Lu P et al. High sensitivity fiber-optic Michelson interferometric low-frequency acoustic sensor based on a gold diaphragm[J]. Optics Express, 28, 25238-25249(2020).

[10] Xia J, Xiong S D, Wang F Y et al. Wavelength-switched phase interrogator for extrinsic Fabry-Perot interferometric sensors[J]. Optics Letters, 41, 3082-3085(2016).

[11] Gao X W, Zhang Z L, Ye B et al[J]. An improved demodulation algorithm of 3×3 coupler for fiber optic hydrophone Acoustics and Electronics Engineering, 2019, 15-19.

[12] Wang W, Tang Y, Zhang X X et al. Elliptical-fitting cavity length demodulation algorithm for compound fiber-optic Fabry-Perot pressure sensor with short cavity[J]. Acta Optica Sinica, 39, 0606001(2019).