Investigations of transient thermal properties of conductively cooled diode laser arrays operating under quasicontinuous-wave conditions

Thermal properties of diode laser arrays not only affect electrical and optical characteristics, they can also become determining factors for long-term reliability of the devices. Here, we report on the investigations of transient thermal effects in high-power diode arrays operating under quasicontinuous-wave (QCW) conditions. A novel measurement setup for the transient junction temperature determination is proposed. We show the measurement results of conductively cooled diode laser arrays mounted on the conventional copper heat sink as well as on the thermal expansion matched CuW submount. The presented results allow evaluation of the thermal cycling experienced by the device during pulsed operation. In the following part, time-resolved wavelength and temperature variations within an array are presented. The guidance for heat sink material choice for high-power diode laser arrays designed for QCW operation is given.