Flip-Chip Bonded Evanescently Coupled III-V-on-Si Single-Mode Laser with Slotted Feedback Structure

A specially designed InP semiconductor optical amplifier (SOA) is flip-chip bonded to the silicon-on-insulator photonic circuit, in which only horizontal alignment is involved reducing the complexity of integration and light is evanescently coupled to the silicon waveguide from the SOA. Two groups of slots are applied as two high-order Distributed Bragg Reflectors (DBR) to select a single mode in the silicon waveguide. Compared with the low-order grating, the slot structure with a feature size in the micrometer level can be fabricated by standard photolithography at a low cost. A single-mode continuous operation with a side mode suppression ratio of more than 30 dB is obtained and the measured output power is 2.5 mW with a threshold current of 116 mA at 20 degrees C. The integrated III-V-on-Si single-mode laser with slotted feedback structure provides a low-cost solution for light sources on silicon.