Non-Volatile Trimming of Photonic Micro-Rings using Integrated and Electrically Programmable Phase-Change Elements

Photonic integrated circuits (PICs) are constantly finding new applications, yet their performance is frequently compromised by unavoidable fabrication errors. Conventional post-fabrication correction methods are often irreversible or power-intensive, limiting the scalability of photonic systems. In this work, we introduce a non-volatile and reversible trimming solution for foundry fabricated PICs using integrated phase-change materials (PCMs). By leveraging a CMOS-compatible waveguide-integrated microheater, we achieve precise control over the PCM’s refractive index, enabling in-situ correction of device performance. We experimentally validate this technique on microring resonator-based components, including wavelength division multiplexers and matrix-vector multipliers (MVM). Our results also identify an important design trade-off, linking PCM thickness directly to the achievable tuning range versus intrinsic device metrics such as the quality factor and extinction ratio. This work establishes a scalable, reversible and non-destructive pathway for post-fabrication correction, paving the way for the reliable, large-scale deployment of photonic integrated circuits.