Thermal characteristics simulation of semiconductor lasers packaging for high speed application

Thermal relaxation time can be critical in high speed optoelectronic devices. In this paper, a three-dimensional thermal model of a semiconductor laser package is developed by the finite element method. A proper designed proportion-integration-differentiation loop is designed for temperature managing. Factors affecting thermal relaxation time in the device are analyzed. Thermal time constant of thermistor and submount are obtained from the simulation. Results show that different materials used for submount can influence the thermal constant time from several hundred microseconds (carbon nanotube) to several hundred milliseconds (AIN, invar). A method of reducing the height of thermistor to increase the temperature detecting speed is proposed, which is necessary when the response speed of the submount is fast. These results could be useful for optoelectronic devices packaging for high speed applications.