Etched Facet Quantum Dot Lasers with U-Turn and Turning Mirror Integration for Silicon Photonics

The integration of group III-V gain devices on silicon photonics (SiPh) is a key technology for next-generation communications systems and data interconnects [1]. Group III-V materials with direct bandgap provide efficient light sources. SiPh leverages mature CMOS manufacturing and can realize complex photonics systems with low loss waveguides. Micro-transfer print (MTP) integration can transfer semiconductor devices from their native substrates to silicon wafers with polydimethylsiloxane (PDMS) stamps [2]. This technique can realize low cost and high throughput integration, however, more research is required to improve the manufacturing process and achieve higher coupled optical power. Quantum dot (QD) gain can improve laser performance with the advantages of low threshold current, high optical power, high wall-plug efficiency, high temperature operation, and robustness to back reflection [3]. This work demonstrates a promising approach to integrate etched facet QD Fabry-Perot (FP) lasers with waveguide turns for MTP integration. FP lasers with two types of waveguide turns were designed, fabricated and characterized to compare the turn structure loss. The integration requires only precision alignment on one side of the coupon and has the potential to achieve high coupling efficiency with optical facets on the same side of the coupon.