Publication
ECTC 2019
Conference paper

Flip-chip III-V-to-silicon photonics interfaces for optical sensor

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Abstract

We demonstrate flip-chip solder assembly of InP chips on Silicon-Photonic (Si-Ph) substrates aimed at high volume manufacturing using typical microelectronic lead-free solders. In our show-case application, an InP die is both a light source and a detector in an integrated optical methane gas sensor that operates near 1.6mm. For high-resolution laser absorption spectroscopy sensing, a single-mode tunable laser is desired. We create an external cavity laser with InP as optical gain, butt-coupled to a Si-Ph external cavity, which incorporates the laser's frequency selective elements. For minimal reflection at the InP-Si interface, waveguides are angled to the facet, an index-matching medium is applied between the mating surfaces, and an anti-reflection coating designed for the index-matching medium is applied to the optical coupling facet of InP chip. Sub-micron alignment accuracy is obtained without high-accuracy assembly tooling. Lithographically defined alignment features on both InP and Si components allow reproducible high-accuracy alignment. Interface throughput loss were measured to be as low as 1.4 dB, and interface reflections are more than 30dB smaller than main signal beams.

Date

01 May 2019

Publication

ECTC 2019

Authors

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