Integrated Avalanche Photodetectors for Visible Light

TL;DR

This paper introduces the first monolithically integrated avalanche photodetector for visible light, demonstrating high gain-bandwidth and low dark current, suitable for sensing and communication applications.

Contribution

It presents a novel integrated visible-light avalanche photodetector based on doped silicon waveguides with high performance metrics.

Findings

High gain-bandwidth product of 216 GHz at 20 V bias

Low dark current of 0.12 μA

Competitive performance compared to infrared APDs

Abstract

Integrated photodetectors are essential components of scalable photonics platforms for quantum and classical applications. However, most efforts in the development of such devices to date have been focused on infrared telecommunications wavelengths. Here, we report the first monolithically integrated avalanche photodetector (APD) for visible light. Our devices are based on a doped silicon rib waveguide with a novel end-fire input coupling to a silicon nitride waveguide. We demonstrate a high gain-bandwidth product of 216 $\pm$ 12 GHz at 20 V reverse bias measured for 685 nm input light, with a low dark current of 0.12 $\mu$A . This performance is very competitive when benchmarked against other integrated APDs operating in the infrared range. With CMOS-compatible fabrication and integrability with silicon nitride platforms, our devices are attractive for visible-light photonics applications in sensing and communications.