Refractive Index Sensing With Mach-Zehnder Interferometer Based on Concatenating Two Single-Mode Fiber Tapers

• Published in: IEEE photonics technology letters Vol. 20; no. 8; pp. 626 - 628
• Main Authors: Zhaobing Tian, Yam, S.S.-H., Barnes, J., Bock, W., Greig, P., Fraser, J.M., Loock, H.-P., Oleschuk, R.D.
• Format: Journal Article
• Language: English
• Published: New York IEEE 15-04-2008; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Bragg gratings; Fiber gratings; Fiber tapers; Insertion loss; long-period grating (LPG); Mach-Zehnder (MZ) interferometer; Optical device fabrication; Optical fiber devices; Optical fiber sensors; Optical fibers; Optical interferometry; Optical sensors; Refractive index; refractive index (RI) sensor
• ISSN: 1041-1135; 1941-0174
• DOI: 10.1109/LPT.2008.919507

A novel refractive index (RI) sensor based on a fiber Mach-Zehnder interferometer was realized by concatenating two single-mode fiber tapers separated by a middle section. The proposed device had a minimum insertion loss of 3 dB and maximum interferometric extinction ratio over 20 dB. The resolution (0.171 nm) of the two-taper sensor to its surrounding RI change (0.01) was found to be comparable to that (0.252 nm) of similar structures made from an identical long-period gratings pair, and its ease of fabrication makes it a low-cost alternative to existing sensing applications.