Ultra-Dense III-V-on-Silicon Nitride Frequency Comb Laser

A heterogeneously integrated III-V-on-silicon nitride mode-locked laser is demonstrated. The device is fabricated by microtransfer printing an InP/InAlGaAs-based multiple-quantum-well coupon. A dense comb with a 755 MHz repetition rate, a 1 Hz ASE limited RF linewidth and a 200 kHz optical linewidth is achieved.