Time Domain Sensing in Abrupt Fiber Taper based Mach-Zehnder Interferometer

A new time domain sensing scheme using a compact single abrupt taper-based standard single mode fiber Mach-Zehnder interferometer is proposed, tested and simulated. The interferometer consists of cascaded symmetrical abrupt 3 dB taper regions separated by a middle interfering section. After the interfering middle section, the cladding modes are converted back into core mode. Due to the external stimuli applied to the interferometer, change of refractive index and the optical path length are induced, resulting in phase difference of core and cladding modes, and hence, the output optical signal in the time domain. The proposed scheme promises a simple and sensitive approach to optical sensing.