Optical filters based on ring resonators with integrated semiconductor optical amplifiers in GaInAsP-InP

A key device in all-optical networks is the optical filter. A ring resonator filter with an integrated semiconductor optical amplifier (SOA) on the basis of GaInAsP-InP has been investigated and fabricated. A required passband shape of loss-compensated ring resonator filters can be custom-designed by the use of multiple coupled resonators. Results of single-, double-, and triple-ring resonators with integrated SOAs with free spectral ranges of 12.5, 25, and 50 GHz, respectively, are presented. A box-like filter response is obtained by the double- and triple-ring resonators using specific coupling coefficients.