Title :
Single-Mode Fiber Refractive Index Sensor Based on Core-Offset Attenuators
Author :
Tian, Zhaobing ; Yam, Scott S H ; Loock, Hans-Peter
Author_Institution :
Dept. of Phys., Queen´´s Univ., Kingston, ON
Abstract :
Mach-Zehnder and Michelson interferometers using core-offset attenuators were demonstrated. As the relative offset direction of the two attenuators in the Mach-Zehnder interferometer can significantly affect the extinction ratio of the interference pattern, single core-offset attenuator-based sensors appear more robust and repeatable. A novel fiber Michelson interferometer refractive index (RI) sensor was subsequently realized by a single core-offset attenuator and a layer of ~ 500-nm gold coating. The device had a minimum insertion loss of 0.01 dB and maximum extinction ratio over 9 dB. The sensitivity (0.333 nm) of the new sensor to its surrounding RI change (0.01) was found to be comparable to that (0.252 nm) of an identical long period gratings pair Mach-Zehnder interferometric sensor, and its ease of fabrication makes it a low-cost alternative to existing sensing applications.
Keywords :
Mach-Zehnder interferometers; Michelson interferometers; extinction coefficients; fibre optic sensors; light interference; refractive index measurement; sensitivity; Mach-Zehnder interferometer; Michelson interferometer; core-offset attenuators; extinction ratio; gold coating; insertion loss; interference pattern; sensor sensitivity; single-mode fiber refractive index sensor; Attenuators; Coatings; Extinction ratio; Gold; Interference; Mach-Zehnder interferometers; Optical fiber devices; Optical fiber sensors; Refractive index; Robustness; Fiber attenuator; Mach–Zehnder interferometer; Michelson interferometer; refractive index (RI) sensor;
Journal_Title :
Photonics Technology Letters, IEEE
DOI :
10.1109/LPT.2008.926832