On the Impact of Mechanical Constraint on Band Structure and Photo‐Elastic Effect in Photonic Resonators

Germanium–tin (GeSn) microdisks have emerged as promising structures for CMOS‐compatible light sources. Their emission properties depend on the composition of the GeSn alloy, strain, and temperature. In particular, optical and electronic properties are sensitive to the distribution of mechanical strain introduced during the growth process and patterning steps. Understanding how mechanical constraints and structural configurations influence the optical mode confinement and band structure is crucial for optimizing GeSn‐based laser devices. In this work, we present a comprehensive computational investigation into the mechanical deformation and optical behavior of GeSn microdisks fabricated on silicon substrates combining photoelasticity, analysis of optical modes and band structure calculations.