Process Variation-Aware Compact Model of Strip Waveguides for Photonic Circuit Simulation

TL;DR

This paper introduces a process variation-aware compact model for strip waveguides that accurately predicts loss, phase, and thermo-optic effects, enabling improved circuit-level simulation of photonic components.

Contribution

It presents a novel model incorporating process variations and thermo-optic effects, with a new group extraction method for high-accuracy parameter estimation.

Findings

Model accurately describes waveguide phase, loss, and thermo-optic behavior.

Experimental validation across wide bandwidths, widths, and temperatures.

Effective for multi-mode waveguides up to 2.5 μm wide.

Abstract

We report a novel process variation-aware compact model of strip waveguides that is suitable for circuit-level simulation of waveguide-based process design kit (PDK) elements. The model is shown to describe both loss and -- using a novel expression for the thermo-optic effect in high index contrast materials -- the thermo-optic behavior of strip waveguides. A novel group extraction method enables modeling the effective index's ($n_{\mathrm{eff}}$) sensitivity to local process variations without the presumption of variation source. Use of Euler-bend Mach-Zehnder interferometers (MZIs) fabricated in a 300~mm wafer run allow model parameter extraction at widths up to 2.5~$\mu$m (highly multi-mode) with strong suppression of higher-order mode excitation. Experimental results prove the reported model can self-consistently describe waveguide phase, loss, and thermo-optic behavior across all measured devices over an unprecedented range of optical bandwidth, waveguide widths, and temperatures.