Silicon Photonics WDM Transceiver with SOA and Semiconductor Mode-Locked Laser

TL;DR

This paper demonstrates a silicon photonics WDM transceiver using a single semiconductor mode-locked laser and SOA, achieving high data rates and error-free operation suitable for datacenter interconnects.

Contribution

It provides the first comprehensive link budget analysis of a silicon photonics WDM transceiver with a semiconductor mode-locked laser, highlighting its potential for low latency datacenter applications.

Findings

Supports up to 12 channels at 14 Gbps with BER of 1e-12

Individual channels operate error-free at 25 Gbps

Scalability limited by SOA saturation and nonlinear effects

Abstract

We demonstrate a complete Silicon Photonics WDM link relying on a single section semiconductor mode-locked laser and a single SOA to support up to 12 multiplexed channels with a bit error rate of 1e-12 at serial data rates of 14 Gbps without channel pre-emphasis, equalization or forward error correction. Individual channels reach error free operation at 25 Gbps and multi-channel operation at 25 Gbps is shown to be compatible with standard 7% overhead hard decision forward error correction. Silicon Photonics transmitter and receiver chips are hybridly integrated with driver and receiver electronics. A detailed link model is derived and verified. Particular emphasis is placed on accurate system level modeling of laser RIN, SOA amplified spontaneous emission noise and receiver noise. The impact of the electrical receiver bandwidth and non-Gaussian statistics on level dependent amplified spontaneous emission noise are investigated in detail. The channel count scalability as limited by SOA saturation is further analyzed taking cross gain modulation and four wave mixing into account. While semiconductor mode-locked lasers have been identified as a potential light source for low cost Datacom WDM transceivers for some time, this is, to the best of our knowledge, the first comprehensive investigation of the overall link budget in a Silicon Photonics implementation showing this technology to be a credible contender for low latency datacenter interconnects.