Box-like filter response of triple ring resonators with integrated SOA sections based on GaInAsP/InP

Triple coupled ring resonator (TRR) add/drop filters with parallel and serial configurations with integrated semiconductor optical amplifiers (SOAs) were designed and fabricated. The implemented SOAs within the resonators offer loss compensation plus additional device functionality. The high order filters have passband characteristics with sharper roll-off, flatter tops, and greater out-of-band rejection than previously demonstrated first order ring resonator filters. The free spectral range (FSR) of the devices is 25 GHz and 50 GHz. An on-off ratio of more than 20 dB was realized. The characteristic response of designed and manufactured triple ring resonator filters with codirectional couplers and integrated semiconductor optical amplifiers are presented.