An Electronic-Photonic Converged Adaptive-Tuning-Step Pipelined Time-Division-Multiplexing Control Scheme for Fast and Scalable Wavelength Locking of Micro-Rings

This paper proposes an electronic-photonic converged adaptive-tuning-step (ATS) pipelined time-division-multiplexing (PTDM) scheme to achieve fast wavelength locking of multiple micro-ring resonators (MRRs) using a shared controller without deteriorating the locking accuracy. The ATS technique breaks the trade-off between wavelength tracking speed and locking accuracy. The PTDM control enables controller sharing while maintaining a high loop bandwidth by exploiting the speed mismatch between the heater and the controller. Custom-designed integrated circuits provide interfacing and clocking functions. A hybrid-integrated four-channel prototype of the proposed scheme has demonstrated a record-breaking tracking speed of 180 nm/s with a locking accuracy of about 7 pm and a tuning range of about 9 nm. This scheme could be extended to applications with dozens or even hundreds of MRRs.