Bandpass Filter With Variable Bandwidth Based on a Tapered Fiber With External Polymer Cladding

Abstract

A thermo-optical bandwidth-variable fiber-based bandpass filter is experimentally and theoretically demonstrated by simply utilizing a tapered standard single-mode fiber covered with a dispersive polymer layer. The 3-dB spectral bandwidth can be tuned from 250 to 500 nm with the filter center wavelength around 1 mu m.