An inline ultrasensitive temperature sensor based on liquid-filled photonic crystal fiber Mach-Zehnder modal interferometer

Abstract

We propose an ultrasensitive temperature sensor based on an in-line liquid-filled photonic crystal fiber (PCF) Mach- Zehnder interferometer. It consists of a small piece of index-guiding PCF fully infiltrated by fluid and two standard single-mode fibers offset spliced with the PCF. Two core modes of LP₀₁ mode and LP₁₁ mode are conveniently utilized as optical arms to form an in-line Mach-Zehnder-type interferometer. Experimental and theoretical investigation of its response to temperature confirms that and a high temperature sensitivity up to -0.244nm/(^oC-mm) could be realized by such a compact inline liquid-filled PCF Mach-Zehnder interferometer.