Echelle Gratings with Metal Reflectors in Generic Thick Silicon Technology

TL;DR

This paper demonstrates the fabrication and performance of Echelle Grating multiplexers with metal reflectors in generic thick Silicon technology, achieving comparable results to specialized processes and providing insights for future design improvements.

Contribution

It introduces the use of metal reflectors in generic thick Silicon Echelle Gratings, expanding fabrication options and performance understanding for integrated photonics multiplexers.

Findings

Achieved 5 dB insertion loss in multiplexers

Demonstrated multiplexers covering C-band and partial S/L bands

Compared performance of devices with and without metal mirrors

Abstract

In this paper, the experimental demonstration of Echelle Grating multiplexers in generic thick Silicon technology, using metal reflectors, is reported. Two multiplexer designs are shown, covering the C-band and partially the S and L bands, with 4 and 8 channels respectively. The multiplexers exhibited performance similar to previously reported devices on dedicated manufacturing processes. The average figures measured are insertion loss 5 dB, loss non-uniformity 3 dB, polarization dependent loss 0.6 dB, polarization dependent wavelength shift of 0.3 nm, with reduced footprint. The performance comparison between multiplexers with and without metal mirrors, for both polarizations, is provided. Several dies were measured, and the passband features for the multiplexers are analyzed, giving a reference on the process variations for future designers.