Theoretical And Experimental Study On All-optical Package Clock Recovery

With the development of times, the people's demand for information is rising. Therefore one trend of telecommunication technology is to upgrade communication capacity of networks.Nowadays, switching in electricity is the main obstacle to upgrade communication capacity of networks. In order to break through this obstacle, technical innovation should be come up. As a result of optical fiber communication, all optical packet switching is becoming the most popular solution to upgrade communication capacity of networks. And all optical packet clock recovery is the most important foundation of all optical packet switching.In this dissertation, we propose a novel solution of all optical packet clock recovery in 10Gbps and 40Gbps. The structure of this solution is"F-P+SOA". Because low finesse F-P (Fabry-Perot filter) ensures that the clock locks fast and vanishes quickly, low finesse F-P is employed to directly extract packet clock in this solution. But the disadvantage for all optical packet clock recovery is that low finesse F-P can't suppress low-frequency noise. Therefore Semiconductor optical amplifier (SOA) follows F-P so that the utilization of self gain modulation (SGM) suppresses the low-frequency noise.In chapter 2, the introduction of F-P's common structure and clock-recovery theory is given, and mathematical expressions of the transmission function, finesse and free spectral range (FSR) is deducted. Then in time and frequency domains, we prove that F-P filter has the ability of extracting clock pulses from packet data signals, and research the F-P parameters'influence on all optical packet clock recovery. Based on the analysis above, we draw a conclusion that low finesse F-P ensures clock setup time and clock release time is enough short, but is a disadvantage for the quality of recovery packet clock.In chapter 3, the analysis of Semiconductor optical amplifier is the primary coverage. Firstly Mathematical models of current carrier density equation, gain and the transmission function are introduced and analyzed in theoretical and numeric. In the process of the analysis, we deeply comprehend the reshaping function of SOA, and input beam power's and SOA's influence on suppressing the amplitude jitter. As a result, the conclusion is obtained that SOA has great effect on suppressing low frequency noise. Meanwhile, we analyze the cross gain modulation (XGM) and cross phase modulation. (XPM), and research the influence of SOA and input beam's parameters on XGM and XPM in theoretical and numeric. Based on the analysis of XGM and XPM., we mathematical analyze and simulate wavelength conversion at 40Gbps. We lay the foundation of the experiments in chapter 4 by the analysis above.In chapter 4, 10Gbit/s and 40Gbit/s all optical packet clock extraction experiment is performed. And the result demonstrates that this solution can extract high quality packet clock, and the period of setup time and release time is enough short too.