Wavelength-tunable fiber codirectional coupler filter based on asymmetric side-polished fiber coupler with dispersive interlayer

Abstract

We demonstrate tunable highly wavelength-selective filter with a coupling ratio of higher than 30 dB based on an asymmetric side-polished fiber coupler with dispersive interlayer in one of the coupling arms. The coupling wavelength can span over 84 nm (from 1410 nm to 1325 nm) under index variation of 0.004.