Heterogeneously integrated InGaP/Si waveguides for nonlinear photonics

The heterogeneous integration of III-V semiconductors with the Silicon platform enables the merging of photon sources with Silicon electronics while allowing the use of Silicon mature processing techniques. However, the inherent sufficient quality of III-Vs' native oxides made imperative the use of deposited interfacial oxide layers or adhesives to permit the bonding. Here we present a novel approach enabling the heterogeneous integration of structured III-V semiconductors on silicates via molecular bonding at 150 °C, much below the CMOS degradation temperature, is presented. The transfer of 235 nm thick and 2 mm long InGaP waveguides with widths of 4.65, 2.6 and 1.22 μm on 4 μm thick Si thermal oxide, with optional SX AR-N 8200.18 cladding, has been experimentally verified. Post-processing of the 1.20 and 0.60 μm input/output tappers has allowed the implementation of double-inverse tapers. The minimal processing requirements and the compatibility with transferring non-cladded structures of the presented technique are demonstrated. The quality of the transferred waveguides bonding interface and their viability for non-linear optics applications has been tested by means of the surface contribution to the optical non-linearity via modal phase-matched second-harmonic generation.