Microwave optical filters based on a fibre Bragg grating in a loop structure

Abstract

A new optical transversal filter structure that features a large number of taps using a single Bragg grating in an active loop is presented. The topology has been used to realise high Q microwave bandpass filters. The impulse response has demonstrated well in excess of 50 taps with precise characteristics. The frequency response demonstrates high resolution having a narrowband bandpass response with a Q of 200. This structure also has the capability for tunable operation.