Field programmable silicon microring WDM transceiver leveraging monolithically integrated phase-change materials

Silicon microring resonators (MRRs) with embedded PN junctions have emerged as pivotal components in high-capacity optical interconnects, serving as modulators or photodetectors due to their compact size, low power consumption, high bandwidth, and inherent wavelength selectivity. However, their resonance wavelengths are highly sensitive to fabrication-induced variations—nanometer-scale deviations in waveguide dimensions can result in significant resonance shifts—necessitating effective post-fabrication tuning mechanisms. Conventional solutions like integrating thermal phase shifters with MRRs enable wavelength tuning but at the cost of increased power consumption. Additionally, various wavelength trimming techniques including germanium ion implantation, continuous laser trimming, femtosecond laser trimming, and polymer material cladding, either have a limited tuning range or require a complex system, and hence they are not suitable for field programming of resonance wavelength. In this work, we introduce a novel integration of low-loss phase change material Sb2Se3 directly atop the PN junctions of silicon MRRs, enabling precise post-fabrication resonance trimming without altering the MRR physical dimensions or performance characteristics. By applying a forward-biased electrical pulse through the PN junction, we induce a phase transition in the Sb2Se3, achieving resonance wavelength tuning across an entire free spectral range (FSR) with minimal impact on modulation and detection capabilities and without the need for extra heating pads. We demonstrate the effectiveness of this method by uniformly aligning the resonance wavelengths of four cascaded SbSe-integrated MRRs, each capable of 100 Gbps on–off keying (OOK) modulation and detection, culminating in a combined data rate of 400 Gbps. Additionally, as enabled by such unique programmability, we propose a feedback scheme to counteract ambient temperature fluctuations as a real-time thermal management strategy during operation, employing one of the MRRs as an optical power monitor to stabilize the modulation of the remaining resonators. Via the non-volatile programmability, our approach significantly reduces static power consumption associated with wavelength adjustment. The use of a PN junction to trigger phase transition with forward-biased electrical pulses not only facilitates the in-situ wavelength trimming but also preserves the MRR perimeter with enough FSR to support the number of channels available for wavelength multiplexing. These advancements position Sb2Se3-integrated MRRs as a promising solution for large-scale, energy-efficient photonic transceivers in next-generation optical communication systems.