Properties of optical phase-locked loop based on four wave mixing in semiconductor laser amplifiers

In this paper, the properties of the optical phase-locked loop(PLL) based o n the four-wave mixing in the semiconductor laser amplifiers (SLAs) are dis cussed. The components that achieve the function of detecting the bit phase of the input optical signal are concerned and discussed in detail together as a function module named as the optical bit phase detector referred to t he general electronic PLL. Therefore, most of the properties of the optical PLL can be analyzed by applying the general phase-locked theory. Here the stability of the optical PLL is discussed. It's shown that the variance of input signal power in the practical application will cause optical PLL syst em unstable because of its long loop delay. The influence on the output pha se jitter of the optical PLL is also investigated.