Intensity modulated refractive index sensor based on optical fiber Michelson interferometer

• Published in: Sensors and actuators. B, Chemical Vol. 208; pp. 315 - 319
• Main Authors: Zhou, Jiangtao, Wang, Yiping, Liao, Changrui, Sun, Bing, He, Jun, Yin, Guolu, Liu, Shen, Li, Zhengyong, Wang, Guanjun, Zhong, Xiaoyong, Zhao, Jing
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.03.2015
• Subjects: Fresnel reflection; Michelson interference; Optical fiber sensor; Reflective index sensor; Temperature insensitivity; Michelson interference; Fresnel reflection; Temperature insensitivity; Reflective index sensor; Optical fiber sensor
• ISSN: 0925-4005; 1873-3077
• DOI: 10.1016/j.snb.2014.11.014

•We fabricated a high-sensitive refractive index sensor based on in-fiber Michelson interferometer.•The sensor has a high sensitivity of −202.46dB/RIU at the refractive index of 1.42.•The proposed sensor overcomes the cross-sensitivity problem between refractive index and temperature via intensity modulation.•The sensor could apply in the fields of chemical and biomedical sensing due to the advantages of short size (less than 8mm) and ultra-simple sructure. We demonstrated a refractive index (RI) sensor based on optical fiber Michelson interferometer (MI), which was fabricated by splicing a section of thin core fiber (TCF) to a standard single mode fiber with a core offset. Experimentally, such a MI-based RI sensor with a core offset of 8μm and a TCF length of 3mm exhibits a high resolution of 4.9×10−6RIU and sensitivity of −202.46dB/RIU, which is two or three times higher than that of intensity-modulated RI sensors reported previously. In contrast, our MI-based RI sensor is insensitive to temperature, thus overcoming the cross-sensitivity problem between surrounding RI and temperature. Moreover, intensity modulation, rather than wavelength modulation, was used in the proposed MI-based RI sensor, and the sensor also has the advantages of compact size (8mm), simple structure, easy fabrication, and good repeatability.