Thermal characteristics of surface liquid crystal vertical cavity surface emitting laser arrays

Abstract

In recent years, with the increase of information processing capacity of optical networks and the continuous improvement of high-density optical communication technology, the requirements for the performance of light sources are also increased. High-quality VCSEL with beam polarization stability control plays an increasingly important role in the above fields. The combination of liquid crystal and vertical cavity surface emitting laser (VCSEL) array can realize wavelength tunability and precise polarization control. At the same time, the introduction of liquid crystal will also change the thermal characteristics of VCSEL array. In this paper, the structure of VCSEL array is designed and the experimental research on the thermal characteristics of VCSEL array is carried out. The effects of nematic liquid crystal layer on the thermal characteristics of VCSEL array are compared and analyzed. The experimental results show that the threshold current temperature change rate of 1 × 1, 2 × 2 and 3 × 3 surface liquid crystal VCSEL array can be reduced by 23.6% and the thermal resistance can be reduced by 26.75%. Moreover, the saturated optical power of VCSEL array can be improved to a different degree. Meanwhile, the liquid crystal layer can effectively increase the heat transverse conduction and reduce the optical hole. The temperature difference between the light outlet and the table makes the heat conduction time very short at a small distance between the light outlet and the table, which is more conducive to the uniform temperature distribution of the laser array. The experimental results show that the temperature difference between the light outlet and the surrounding is less than 0.5 ℃. To sum up, the introduction of liquid crystal layer into VCSEL array not only greatly accelerates the thermal diffusion of laser array unit, but also reduces the junction temperature of active region, improves the thermal characteristics of VCSELs laser array, and lays a good theoretical and experimental foundation for realizing the high beam quality single polarization wavelength controllable VCSEL laser array.