GaInAsP/silicon-on-insulator hybrid laser with ring-resonator-type reflector fabricated by N₂ plasma-activated bonding

III–V/Si hybrid integration with direct bonding is an attractive method of realizing an electrophotonic convergence router with a small size and a low power consumption. Plasma-activated bonding (PAB) is an effective approach for reducing thermal stress during the bonding process because PAB achieves a high bonding strength with low-temperature annealing. This time, the fabrication of a GaInAsP/silicon-on-insulator (SOI) hybrid laser with Si ring-resonator-type reflectors was demonstrated by N 2 PAB. By measuring the lasing spectra, we confirmed the reflective characteristics resulting from the cascaded Si ring resonators. We also investigated kink characteristics, which occur around the threshold current, of the current–light output ( I – L ) characteristics, and successfully approximated the kink characteristics by considering saturable absorption occurring at the III–V/Si taper tip. The taper structure was investigated in terms of a passive device as well as an active device, and a structure for eliminating saturable absorption was proposed.