An Inline Core-Cladding Intermodal Interferometer Using a Photonic Crystal Fiber

Abstract

We propose a simple all-fiber structure based on intermodal interference between a core and a cladding mode of an endlessly single-mode photonic crystal fiber (PCF) section sandwiched between a lead-in and lead-out SMF-28 fiber. We have measured the intermodal dispersion and the polarization-dependent loss (PDL) of the structure. The sensitivities to strain, pressure, and temperature and external refractive index are studied. The interferometer is compared to an interferometer based on LP <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">01</sub> -LP <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">02</sub> SMF-28 fiber and to a PCF-based tapered LPG.