Wavelength tuning and stabilization of microring-based filters using silicon in-resonator photoconductive heaters

TL;DR

This paper introduces silicon-based photoconductive heaters integrated into microring resonators for automatic wavelength tuning and stabilization, enabling high-speed data transmission without additional complex fabrication steps.

Contribution

The work demonstrates a novel, integrated photoconductive heater approach for automatic resonance stabilization in microring filters without extra fabrication processes.

Findings

Successfully stabilized resonance wavelength in microring filters

Achieved open eye diagrams at 12.5 Gb/s under temperature variations

Theoretically extended tuning method to higher-order filters

Abstract

We demonstrate that n-doped resistive heaters in silicon waveguides show photoconductive effects with high responsivities. These photoconductive heaters, integrated into microring resonator (MRR)-based filters, were used to automatically tune and stabilize the filter's resonance wavelength to the input laser's wavelength. This is achieved without requiring dedicated defect implantations, additional material depositions, dedicated photodetectors, or optical power tap-outs. Automatic wavelength stabilization of first-order MRR and second-order series-coupled MRR filters is experimentally demonstrated. Open eye diagrams were obtained for data transmission at 12.5 Gb/s while the temperature was varied by 5 C at a rate of 0.28 C/s. We theoretically show that series-coupled MRR-based filters of any order can be automatically tuned by using photoconductive heaters to monitor the light intensity in each MRR, and sequentially aligning the resonance of each MRR to the laser's wavelength.