Harmonically Mode-Locked Hybrid Silicon Laser With Intra-Cavity Filter to Suppress Supermode Noise

We present results from two hybrid silicon mode-locked lasers, each with a 2 GHz cavity and one with an intra-cavity ring resonator filter. We compare the performance of the two lasers with respect to the harmonic mode-locking behavior at 20 GHz, i.e., the tenth harmonic. The filter based laser design passively mode-locked at 20 GHz with an electrical spur mode suppression >45 dB. Furthermore, an optical supermode suppression of 55 dB and an RF linewidth of 52 kHz was also observed. Hybrid mode-locking the laser without the filter required 10 dBm input microwave power for 25 dB (electrical) spur mode suppression as opposed to the design with the filter showing >45 dB suppression at 0 dBm input power.