Abstract

The thermal runaway process for long wavelength velocity-matched distributed photodetectors (VMDP) with metal-semiconductor-metal photodiodes has been studied. We developed a numerical, three-dimensional electro­thermal model taking into account the nonlinearity of the substrate thermal properties and the nonuniform temperature rise due to self-heating. The analysis shows that the distributed nature of the photodetector allows it to work at high power level before catastrophic failure occurs. Examples are discussed to highlight the thermal behaviour of the distributed detector and to compare the model with experimental data.