Spatially resolved self-heating and thermal impedance of laser diodes using CCD-TR imaging

The spatial distribution of the surface temperature of single and multi-section slotted semiconductor laser diodes with surface gratings is investigated experimentally with CCD-thermoreflectance imaging. The lasers are single frequency devices, operating at approximately 1550 nm. High resolution temperature maps of the laser ridge are obtained, with spatial resolution near 1 mu m. The temperature profile in the direction lateral to the ridge is presented and a rapid decay in temperature away from the ridge is observed. Acquisition of the temperature maps takes about 8 minutes, with three maps required for a 400 mu m device. The ridge temperature rise is shown to be linear with the power consumed by the diode. The temperature profile along the laser ridge is shown to be uniform within a section of the multi-section laser. The thermal impedance of the single section slotted laser and the various sections of the multi-section slotted laser were determined. It was found that the thermal impedance ridge length product (Z(th)L) was 40 +/- 6 degrees C mu m/mW for all section lengths. Between sections a rapid decay is also observed. (c) 2021 Optical Society of America under the terms of the OSA Open Access Publishing Agreement