Analysis of temperature characteristics of high power vertical cavity surface emitting laser arrays

High-power vertical cavity surface emitting lasers (VCSELs) are widely used in optical communication, optical storage, optical interconnection, sensing, and other fields. High-power VCSELs usually adopt a high-density array layout, and temperature is one of the key factors affecting their performance. In this work, the thermal characteristics of the VCSEL array with 1273 elements have been studied. A series of photoelectric characteristics such as the working voltage, output optical power, slope efficiency, electro-optical conversion efficiency, and spectrum of the device have been analyzed through a precision temperature control system. According to the relationship between the measured wavelength shift and the dissipated power, it is calculated that the thermal resistance value of the device increases from 1.319℃/W to 1.952℃/W, and the temperature rise of the active area is extracted. It can be seen that more temperature rises in the active region at higher ambient temperature for a given injection current, with a maximum value of 105.6℃. A thermo-electric coupling model was established to simulate the thermal distribution. The equivalent array method is employed to simplify the high-density array. The simulated results agree well with the measurement. As the ambient temperature rises, the thermal crosstalk phenomenon in the VCSEL array becomes more obvious. Heat diffusion becomes more difficult, resulting in more heat accumulation inside the device. The internal loss of the device is severe and the gain-cavity mode is seriously mismatched, so the photoelectric performance decays sharply. This research provides important guidance for the optimization and application of future devices.