Electric-arc-induced long period grating filters fabricated with dual concentric core fibers

Abstract

We have fabricated Long Period Grating filters in two Dual Concentric Core Fibers by an electric arc discharge technique. The gratings have induced coupling between the fundamental modes of the two cores. We have obtained filter with rejected band around 1220 nm and 1559 nm respectively, characterized by insertion loss lower than 0.5 dB. We also have investigated the inteest of using this fiber to implement a highly selective Mach-Zehnder interferometer with a 2.4 nm inter-fringe. Despite the high Ge-doping of the used fiber, thermal characterizations show a temperature sensitivity of the transmitted spectrum similar to that of the same grating written in a standard Single Mode Fiber.