Electro-Absorption Modulator Thermo-Optical Self-Heating Analysis

In this work a novel methodology is presented for coupled thermo-optical modelling of an electro-absorption modulator (EAM). First, an optical FDTD simulation results in the light absorption map in the EAM waveguide. This absorption is used as a heat source boundary condition in a thermal finite element (FE) simulation in order to calculate the waveguide temperature. The FE model is validated with experimental data. The temperature is averaged over the device length and used as input in a compact, fully coupled thermo-optical model. The model reveals a thermal instability of the device characteristic, which limits the maximum amount of optical power the device can handle. Finally, using the thermal FE model, a self-heating mitigation strategy is proposed. Using process compatible design changes, self-heating can be reduced by up to 40%, greatly increasing the EAM optical power handling capabilities.