Thermo-Optical Analysis of O-Band GeSi Quantum Confined Stark Effect Electro-Absorption Modulators

High speed, highly efficient, ultra-compact, and thermally stable modulators are needed to meet the increasing growth in datacenter traffic. This letter demonstrates the temperature-dependent DC performance and reliability study of O-band GeSi quantum confined stark effect (QCSE) electro-absorption modulators (EAM) integrated in a 300 mm silicon photonics platform. The modulator with a width of $2~\mu $ m and a length of $36.8~\mu $ m demonstrated thermal stability in the measurement range of $25~^{\circ }$ C to $75~^{\circ }$ C, with a mean value of the band edge shift coefficient of 0.59 nm/°C. The optimum extinction ratio (ER) undergoes a red shift and is preserved at higher temperatures. The self-heating of the device due to optical absorption is assessed using finite element (FE) simulations, and it is found to be <5 K in most operating conditions. Our results emphasize the promise of the GeSi QCSE EAM for next-generation optical I/O applications.