Numerous communication techniques and optical devices successfully applied in space optical communication system indicates a good portability of it. With this good portability, typical coherent demodulation technique of Costas loop can be easily adopted in space optical communication system. As one of the components of pointing error, the effect of jitter plays an important role in the communication quality of such system. Here, we obtain the probability density functions (PDF) of different jitter degrees and explain their essential effect on the bit error rate (BER) space optical communication system. Also, under the effect of jitter, we research the bit error rate of space coherent optical communication system using Costas loop with different system parameters of transmission power, divergence angle, receiving diameter, avalanche photodiode (APD) gain, and phase deviation caused by Costas loop. Through a numerical simulation of this kind of communication system, we demonstrate the relationship between the BER and these system parameters, and some corresponding methods of system optimization are presented to enhance the communication quality.
CMOS is a good candidate tracking detector for satellite optical communications systems with outstanding feature of
sub-window for the development of APS (Active Pixel Sensor) technology. For inter-satellite optical communications
it is critical to estimate the direction of incident laser beam precisely by measuring the centroid position of incident beam
spot. The presence of detector noise results in measurement error, which degrades the tracking performance of systems.
In this research, the measurement error of CMOS is derived taking consideration of detector noise. It is shown that the
measurement error depends on pixel noise, size of the tracking sub-window (pixels number), intensity of incident laser
beam, relative size of beam spot. The influences of these factors are analyzed by numerical simulation. We hope the
results obtained in this research will be helpful in the design of CMOS detector satellite optical communications systems.