Laser Integration on Silicon through Flip-chip Bonding with Efficient Coupling

Abstract

Integrated silicon photonics technology has wide applications including communication and sensing. It enables high-capacity data transmission in modern communication systems. In the meanwhile, light source integration on silicon remains to be a challenge to overcome. To achieve laser integration on silicon photonics platform with efficient coupling, in this work, a concept for integration of semiconductor laser on silicon wafer through flip-chip bonding with precise control on vertical direction (Z direction) is proposed. High vertical alignment precision of ± 50 nm can be obtained by a developed selective etching process using an etch stop layer. Furthermore, by using a multi-tip edge coupler, the horizontal misalignment tolerance with flip-chip bonded laser can be improved, with an estimated 1-dB horizontal misalignment tolerance of $0.6\ \mu\mathrm{m}$ obtained from calculation at 1310 nm (O-band). The work paves the way towards efficient electronic-photonic heterogeneous integration.