Hybrid integration of silicon photonics circuits and InP lasers by photonic wire bonding

TL;DR

This paper demonstrates a novel photonic wire bonding technique that efficiently connects InP lasers to silicon photonic circuits with minimal loss, enabling scalable hybrid photonic integration.

Contribution

It introduces photonic wire bonding with two-photon lithography as a new method for low-loss, scalable hybrid integration of III-V lasers and silicon photonics.

Findings

Achieved insertion losses as low as 0.4 dB between InP lasers and silicon circuits.

Demonstrated the most efficient InP-to-silicon interface to date.

Showcased potential for large-scale hybrid photonic multi-chip modules.

Abstract

Efficient coupling of III-V light sources to silicon photonic circuits is one of the key challenges of integrated optics. Important requirements are low coupling losses, as well as small footprint and high yield of the overall assembly, along with the ability to use automated processes for large-scale production. In this paper, we demonstrate that photonic wire bonding addresses these challenges by exploiting direct-write two-photon lithography for in-situ fabrication of three-dimensional freeform waveguides between optical chips. In a series proof-of-concept experiments, we connect InP-based horizontal-cavity surface emitting lasers (HCSEL) to passive silicon photonic circuits with insertion losses down to 0.4 dB. To the best of our knowledge, this is the most efficient interface between an InP light source and a silicon photonic chip that has so far been demonstrated. Our experiments represent a key step in advancing photonic wire bonding to a universal integration platform for hybrid photonic multi-chip assemblies that combine known-good dies of different materials to high-performance hybrid multi-chip modules.