Edge couplers with relaxed alignment tolerance for pick-and-place hybrid integration of III-V lasers with SOI waveguides

Abstract

We report on two edge-coupling and power splitting devices for hybrid integration of III-V lasers with sub-micrometric silicon-on-insulator waveguides.The proposed devices relax the horizontal alignment tolerances required to achieve high coupling efficiencies and are suitable for passively aligned assembly with pick-and-place tools. Light is coupled to two on-chip single mode SOI waveguides with almost identical power coupling efficiency, but with a varying relative phase accommodating the lateral misalignment between the laser diode and the coupling devices, and is suitable for the implementation of parallel optics transmitters. Experimental characterization with both a lensed fiber and a Fabry-Pérot semiconductor laser diode has been performed. Excess insertion losses (in addition to the 3 dB splitting) taken as the worst case over both waveguides of respectively 2 ± 0.3 dB and 3.1 ± 0.3 dB, as well as excellent 1 dB loss placement tolerance range of respectively 2.8 and 3.8(worst case over both in-plane axes) have been measured for the two devices. Back-reflections to the laser are below-20 dB for both devices within the 1 dB misalignment range.Devices were fabricated with 193 nm DUV optical lithography and are compatible with mass-manufacturing with mainstream CMOS technology.© 1995-2012 IEEE.