Research of background noise effect on preamplified homodyne detection system

Along with the development of EDFA, the high sensitivity of coherent detection is less attractive than it used to be. However, coherent detection has another advantage of high frequency selectivity, which is still important. In this paper, we investigate a coherent receiver with EDFA as a preamplifier, which has several advantages including relaxed LO power requirement. Numerical results show that the receiver with preamplifier is higher than that of the receiver without preamplifier when the power of LO is less than 10dBm. Besides, we emphatically analyze the background radiation, and find that the power penalty caused by background radiation is about 1.8dB at 1550nm.