[1] H. Song, H. Gong, K. Ni, and X. Dong, “All fiber curvature sensor based on modal interferometer with waist enlarge splicing,” Sensor and Actuators A: Physical, 2013, 203: 103-106.

[2] J. Wo, Q. Sun, X. Li, D. Liu, and P. P. Shum, “Biconical-taper-assisted fiber interferometer with modes coupling enhancement for high-sensitive curvature measurement,” Applied Physics B: Lasers, 2014, 115: 1-8.

[3] Y. Zhao, L. Cai, and X. G. Li, “In-fiber modal interferometer for simultaneous measurement of curvature and temperature based on hollow core fiber,” Optics and Laser Technology, 2017, 92: 138-141.

[4] G. Fu, Y. Li, X. Fu, W. Jin, and W. Bi, “Temperature insensitive curvature sensor based on cascading photonic crystal fiber,” Optical Fiber Technology, 2018, 41: 64-68.

[5] M. Xiong, H. Gong, Z. Wang, C. L. Zhao, and X. Dong, “Fiber curvature sensor based on spherical-shape structures and long-period grating,” Optics and Lasers in Engineering, 2016, 86: 356-359.

[6] C. Luo, P. Lu, J. Chen, S. Wang, C. Zhang, and X. Fu, “All-fiber curvature sensor based on offset splicing structure cascaded with long-period fiber grating,” in Proceeding 14th International Conference on Optical Communications and Networks, Nanjing, China, 2015, pp. 1-3.

[7] X. R. Dong, Z. Xie, Y. X. Song, K. Yin, D. K. Chu, and J. A. Duan , “High temperature-sensitivity sensor based on long period fiber grating inscribed with femtosecond laser transversal-scanning method,” Chinese Optics Letters, 2017, 15(9): 51-55.

[8] Y. Zhou, W. Zhou, C. C. Chan, C. W. Wei, L. Y. Shao, J. Cheng, et al., “Simultaneous measurement of curvature and temperature based on PCF-based interferometer and fiber Bragg grating,” Optics Communications, 2011, 284(24): 5669-5672.

[9] L. Hui, H. Yang, X. Qiao, Y. Wang, X. Liu, Y. S. Lee, et al., “Curvature and temperature measurement based on a few-mode PCF formed M-Z-I and an embedded FBG,” Sensors, 2017, 17(8): 1725-1735.

[10] O. Fraz-o, J. Viegas, P. Caldas, J. L. Santos, F. M. Araújo, L. A. Ferreira, et al., “All-fiber Mach-Zehnder curvature sensor based on multimode interference combined with a long-period grating,” Optics Letters, 2007, 32(21): 3074-3076.

[11] X. Dong, Y. Liu, L. Y. Shao, J. Kang, and C. L. Zhao, “Temperature-independent fiber bending sensor based on a superimposed grating,” IEEE Sensors Journal, 2011, 11(11): 3019-3022.

[12] X. R. Dong, H. F. Du, Z. Luo, K. Yin, and J. A. Duan, “Highly sensitive refractive index sensor based on novel Mach-Zehnder interferometer with multimode fiber-thin core fiber-multimode fiber structure,” Japanese Journal of Applied Physics, 2018, 57(9): 1-5.

[13] H. F. Du, X. Y. Sun, Y. W. Hu, X. R. Dong, and J. H. Zhou, “High sensitive refractive index sensor based on cladding etched photonic crystal fiber Mach-Zehnder interferometer,” Photonic Sensors, 2019, 9(2): 126-134.

[14] X. Y. Sun, X. R. Dong, Y. W. Hu, H. T. Li, D. K. Chu, J. Y. Zhou, et al., “A robust high refractive index sensitivity fiber Mach-Zehnder interferometer fabricated by femtosecond laser machining and chemical etching,” Sensors and Actuators A: Physical, 2015, 230: 111-116.

[15] 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,” Optics Express, 2008, 16(15): 11369-11375.

[16] Y. Ma, X. Q. Qiao, T. A. Guo, R. H. Wang, J. Zhang, Y. Y. Weng, et al., “Mach-Zehnder interferometer based on a sandwich fiber structure for refractive index measurement,” IEEE Sensors Journal, 2012, 12(6): 2081-2085.

[17] Y. Zhao, F. Xia, M. Q. Chen, Y. Zhao, F. Xia, and M. Q. Chen, “Curvature sensor based on Mach-Zehnder interferometer with vase-shaped tapers,” Sensors and Actuators A: Physical, 2017, 265: 275-279.

[18] L. Mao, P. Lu, Z. Lao, and D. Liu, “In-fiber Mach-Zehnder interferometer based on multi-mode fiber and up-taper for curvature sensing,” Optik, 2014, 125(18): 5108-5111.

[19] C. Shen, C. Zhong, H. Gong, J. Wang, J. Chu, X. Zou, et al., “Polarization-dependent curvature sensor based on an in-fiber Mach-Zehnder interferometer with a difference arithmetic demodulation method,” Optics Express, 2012, 20(14): 15406-15417.

[20] Y. Gong, T. Zhao, Y. J. Rao, and Y. Wu, “All-fiber curvature sensor based on multimode interference,” IEEE Photonics Technology Letters, 2011, 23(11): 679-681.

[21] H. P. Gong, H. F. Song, X. R. Li, J. F. Wang, and X. Y. Dong, “An optical fiber curvature sensor based on photonic crystal fiber modal interferometer,” Sensors and Actuators A: Physical, 2013, 195: 139-141.

[22] R. H. Wang, J. Zhang, Y. Y. Weng, Q. Z. Rong, Y. Ma, Z. Y. Feng, et al., “Highly sensitive curvature sensor using an in-fiber Mach-Zehnder interferometer,” IEEE Sensors Journal, 2013, 13(5): 1766-1770.

[23] Y. Zhao, L. Cai, and X. G. Li, “Temperatureinsensitive optical fiber curvature sensor based on SMF-MMF-TCSMF-MMF-SMF structure,” IEEE Transactions on Instrumentation & Measurement, 2016, 66(1): 141-147.

[24] H. Sun, S. Yang, J. Zhang, Q. Z. Rong, L, Liang, Q. F. Xu, et al., “Temperature and refractive index sensing characteristics of an MZI-based multimode fiber-dispersion compensation fiber-multimode fiber structure,” Optical Fiber Technology, 2012, 18(6): 425-429.

[25] Y. M. Raji, H. S. Lin, S. A. Ibrahim, M. R. Mokhtar, and Z. Yusoff, “Intensity-modulated abrupt tapered fiber Mach-Zehnder interferometer for the simultaneous sensing of temperature and curvature,” Optics & Laser Technology, 2016, 86: 8-13.

[26] X. R. Dong, H. F. Du, X. Y. Sun, and J. A. Duan, “Simultaneous strain and temperature sensor based on a fiber Mach-Zehnder interferometer coated with Pt by iron sputtering technology,” Materials, 2018, 11(9): 1535-1545.

[27] C. X. Lu, J. A. Su, X. P. Dong, T. Sun, and K. T. V. Grattan, “Simultaneous measurement of strain and temperature with a few-mode fiber-based sensor,” Journal of Lightwave Technology, 2018, 36(13): 2796-2802.

[28] C. Li, T. G. Ning, C, Zhang, J. Li, C. B. Zhang, X. D. Wen, et al., “All-fiber multipath Mach-Zehnder interferometer based on a four-core fiber for sensing applications,” Sensors and Actuators A: Physical, 2016, 248: 148-154.

[29] L. L. Mao, P. Lu, Z. F. Lao, D. M. Liu, and J. S. Zhang, “Highly sensitive curvature sensor based on single-mode fiber using core-offset splicing,” Optics & Laser Technology, 2014, 57: 39-43.

[30] Y. Wu, L. Pei, W. X. Jin, Y. C. Jiang, Y. G. Yang, and Y. Shen, “Highly sensitive curvature sensor based on asymmetrical twin core fiber and multimode fiber,” Optics & Laser Technology, 2017, 92: 74-79.

[31] Y. Zhao, C. Lu, and X. Li, “Temperature-insensitive optical fiber curvature sensor based on SMF-MMF-TCSMF-MMF-SMF structure,” IEEE Transactions on Instrumentation and Measurement, 2016, 66(1): 141-147.

[32] W. Jin, C. Michie, G. Thursby, M. Konstantaki, and B. Culshaw, “Simultaneous measurement of strain and temperature: error analysis,” Optical Engineering, 1997, 36(2): 598-609.