Tunable microwave/millimeter wave transversal filter using retro-reflective spatial photonics

A novel retro-reflective architecture based radio frequency (RF) transversal filter using a chirp Fiber Bragg Gratings (FBG), an interleaver, and an electronically programmable spatial light modulator (SLM) is presented. This filter features a compact retro-reflective geometry high dynamic range programmable filter design with a compact fiber delay that can provide high resolution RF filter shaping for broadband RF bands. The SLM provides time selection and weighting while the FBG provides wavelength sensitive delay, with the interleaver separating the positive and negative weights. This technique can be combined with wavelength insensitive bias delays to expand the tunability range of the proposed filter.