Optical control of birefringence for loop mirror comb filter tuning using a semiconductor optical amplifier

This work reports on an optically tunable loop mirror comb filter (LMF) incorporated with a SOA and a piece of polarization maintaining fiber (PMF). Optical comb tuning is achieved by injecting a control light into the SOA. By changing the birefringence of the SOA using a control light, an optically controlled comb tuning is successfully demonstrated.