Effect of Amplifier Spontaneous Emission Noise on Performance of Space Chaotic Laser Communication Systems

Recently space communication technology develops rapidly and space chaotic laser communication serves as an excellent scheme to enhance the security of data transmission. To achieve long-distance transmission, Erbium-doped fiber amplifier (EDFA) is used in a space chaotic laser communication system, but this will inevitably bring amplifier spontaneous emission (ASE) noise. In order to investigate the effect of ASE noise, we give a modified bit error rate (BER) calculation model and numerical simulations are conducted based on it. Quantitative results show that most of ASE noise in the system is caused by the EDFA at the receiver rather than the emitter. Apart from this, deeper researches further indicate that ASE noise will induce mismatch. When ASE noise is small, inherent mismatch noise is the main factor causing mismatch. But as ASE noise power becomes larger, mismatch noise will be dominated by external mismatch noise and internal mismatch noise. Our results have a good reference value for the design of space chaotic laser communication systems.