Demonstration and Non-volatile Trimming of a Highly-Parallel, High-Capacity Silicon Microdisk Transmitter

TL;DR

This paper demonstrates a high-capacity silicon microdisk optical transmitter with 1.2 Tb/s bandwidth, utilizing a novel laser trimming technique for permanent wavelength tuning, significantly reducing energy consumption and enabling scalable optical interconnects.

Contribution

It introduces a CMOS-based microdisk transmitter system with 1.2 Tb/s bandwidth and a novel laser trimming method for permanent, low-loss wavelength tuning, improving fabrication tolerance.

Findings

Achieved 1.2 Tb/s off-die bandwidth with 64 microdisks.

Reduced energy consumption for wavelength tuning by 33%.

Enabled a passive 5-channel DWDM transmitter.

Abstract

Optical interconnects are the most promising solution to address the data-movement bottleneck in data centers. Silicon microdisks, benefiting from their compact footprint, low energy consumption, and wavelength division multiplexing (WDM) capability, have emerged as an attractive and scalable platform for optical modulation. However, microdisk resonators inherently exhibit low fabrication error tolerance, limiting their practical deployment. Here, utilizing a CMOS photonics platform, we demonstrate 1.2 Tb/s of off-die bandwidth through a 64 microdisk modulator system. In addition, we develop an automated, close-looped, non-reversible, low-loss, and picometer-precision permanent wavelength tuning technique using laser trimming. The trimming technique reduces 33 % of the energy consumption needed to thermally tune the microdisk resonant wavelength. Using this technique, we achieve a fully passive, 5-channel dense wavelength division multiplexing (DWDM, 50 GHz spacing) transmitter. The integration of the high speed (1.2 Tb/s), low energy consumption (29 fJ/bit) and the permanent wavelength trimming lays a robust foundation for next-generation optical interconnect systems, poised to facilitate scaling of future AI and computing hardware.