III-V/Si heterogeneously integrated photonic devices using chip-on-wafer bonding technology

We comprehensively review III-V/Si heterogeneously integrated photonic devices fabricated through the bonding of InP chips on a silicon-on-insulator wafer using surface hydrophilization with ultra-violet-ozone treatment. The stable continuous-wave operation of 3,000 hours is verified for Fabry-Perot lasers fabricated through this chip-on-wafer bonding process. The heterogeneously integrated tunable laser for C- and L-band operation is demonstrated. This device is consisting of two tunable lasers with the InP-based gain region integrated on a single Si-photonic circuit chip with ring resonators and loop mirrors. It exhibits the extremely wide wavelength tuning range operation of 104 nm, and the side-mode suppression ratio of more than 45 dB and narrow spectral linewidth of less than 50 kHz are achieved over the entire wavelength tuning range. The Mach-Zehnder modulator in which InP-based modulator regions are integrated on Si waveguides indicates high modulation efficiency (Vπ·L: 0.43 V∙cm) and high bandwidth operation (electrical/optical 3 dB bandwidth > 70 GHz). The compact photodetector consisting of the InP-based p-i-n photodiode array integrated on Si-photonic circuits for coherent receivers is also verified, and it exhibits the high responsivity (> 0.1 A/W over the L-band) including the intrinsic loss of 6 dB in a 90° hybrid and fiber coupling loss. From these results, we have revealed that this III-V/Si heterogeneous integration platform is very promising towards the realization of next-generation photonic integrated circuits employing synergistic effects from both III-V compound semiconductors and Si photonics.