Light-Input Tapered SiO[sub x] Facet with InP Crystallographic Slope for InGaAsP–InGaAs–InP Waveguide Photodetectors

Abstract

A high speed waveguide photodetector (WGPD) integrated with a light input tapered SiOx facet that has high efficiency bandwidth product characteristics has been developed using the regrowth-free approach. This approach with monolithic integration is compared with standard processes. The typical excessive surface leakage current density was suppressed by more than 1 order of magnitude (from 115 to 7.4mA/cm2 at −5 V), and the responsivity was increased from 0.4 to 0.75 A/W. The 7μm oxide surrounding the WGPDs can be regarded as a SiOx waveguide in front of the absorption-region aperture and as a dielectric bonding pad capacitance. The proposed WGPD has a 3 dB bandwidth of 17 GHz with a responsivity of 0.75 A/W at a wavelength of 1.3μm under 132.5μW illuminations.