The optical sampling based on semiconductor optical amplifier for optical performance monitoring

Progress in optical network has stimulated interest in optical performance monitoring (OPM). Optical sampling technique is believed to be a promising candidate to monitor the physical state of the network. The theoretical model of a monitoring system based on optical sampling in semiconductor optical amplifier (SOA) and software synchronized algorithm is constructed. Compared with the results obtained by Optsim, the monitoring system model is proved. For 10Gb/s NRZ (RZ) optical signals, the differences on Q values between the results obtained by SOA and the ideal sampling processes are 0.195dB (0.247dB), 0.988dB (0.594dB), and 1.707dB (0.596dB) for pump energy equal to, ten times of and fifty times of the optical data signal energy respectively. The sampling device can induce degradations of the sampling results. It is mainly because of the gain saturation and the nonlinear effects in SOA. The high input power can make the gain saturated deeply and further influence the probe and conjugate outputs. At the same time, the pump power should not be too low. The proper pump power will obtain better sampling linearity and better sampling results.