Effects of temperature distribution on performance of SiC reflectors in periscopic laser communication terminals

Effects of temperature gradient and uniform temperature on reflectors in periscopic laser communication terminals were studied. Zernike polynomials on elliptical aperture were used to fit wave-front aberration of the elliptical reflectors due to temperature distribution. RMS value, pointing error and peak intensity degradation at the receiver caused by thermal deformation were studied in inter-satellite laser communication system. The results show that the effect of temperature gradient cause drift of peak intensity and a little degradation. The pointing error reaches 2.1 μrad when temperature gradient is 14 °C/m. The uniform temperature will cause variation of intensity distribution at the receiver and result in larger pointing error and degradation of intensity. The pointing error is less than 1 μrad when the difference between uniform temperature and reference temperature is less than 0.6 °C. But the pointing error rises rapidly and the intensity distribution changes when the difference is larger than 0.6 °C. The astigmatism caused by thermal distortion is very important.