Electro-Absorption Modulator Thermo-Optical Self-Heating Analysis

• Published in: Journal of lightwave technology Vol. 41; no. 18; pp. 6000 - 6006
• Main Authors: Coenen, David, Oprins, Herman, Berciano, Mathias, Muliuk, Grigorij, Heyn, Peter De, Campenhout, Joris Van, De Wolf, Ingrid
• Format: Journal Article
• Language: English
• Published: New York IEEE 15.09.2023; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Absorption; Boundary conditions; Electro-absorption modulator; Electro-absorption modulators; Electroabsorption modulators; Electromagnetic absorption; Finite element method; Heating; Optical coupling; Optical device fabrication; Optical modulation; Optical sensors; Optical waveguides; Self-heating; Thermal instability; Thermo-optical model; Waveguides
• ISSN: 0733-8724; 1558-2213
• DOI: 10.1109/JLT.2023.3269507

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.