Research Of SPM Compensation In Super-channels Based On Optical Frequency Combs

In the current communication system, since the rapid ly increasing capacity demand and the development of communication technologies, the transmission data rate carried by each channel has reached 100Gbit/s and beyond. Beccause of the bottleneck of the present electronic devices, a higher single-channel rate such as 1-Tbit/s and beyond based on the multi-carrier superchannel are under active research. So far, to realize high capacity superchannel, researchers have proposed many transmissio n systems and modulation schemes, such as AO-OFDM and N-WDM. However, due to the existence of fiber nonlinearity effects in optical fiber transmission, the high launch power will seriously reduce the performance of fiber transmission systems. Therefore, in that case, we considere the CO-OFDM superchannel based on optical frequency comb as the main object of study. On the basis of deeply understanding of key technologies of CO-OFDM, we simulate the effects of nonlinearity and the structure of the superchannel based on optical frequency comb. The main contents of study are as follows:(1) This thesis summarizes the development of traditional optical OFDM techlology and introduces the current trend of optical communication systems, which is ultra high-speed and long- haul optical transmission channe l, such as Tb/s multi-band superchannel.(2) We describe the principles and techniques of CO-OFDM systems, and build a CO-OFDM system through VPI and MTLAB co-simulation platform. And some mathematical models used in the system VPI introduced are introduced.(3) We build a multiple sub-band CO-OFDM superchannel based on optical frequency comb systems, making the signal rate of fiber transmissions reached 1Tb/s or more. First we describe a method for the optical frequency comb generation. Then we use this comb as carriers of signal and LO to form CO-OFDM systems. In the simulation system, we finally realize 32 × 40Gbit/s coherent optical OFDM systems, which transmission rate is up to 1Tb/s or more.(4) We describe the commonly way to reduce the PAPR for the mitigation of nonlinear impact. Firstly we introduce the commonly method of clipping in CO-OFDM system. Secondly we study the” Odds and Evens” cahnnels, and see if it can reduce the PAPR and nonlinear effects.(5) The detailed description and analysis of the design of superchannel optical transmission system are apresented in this paper, and SPM compensation method which is used in this system, and the simulation results are analyzed and discussed. Firstly, using VPI virtual simulation platform, we jointly build a single-band reception system and 4 sub-band reception both in CO-OFDM superchannel system, and then we using SPM compensation in both system, and finally to discuss the effect of compensation obtained from results of simulation. Simulation results show that the SPM compensation is also effective in the multiple sub-bands superchannel as in the single-band system.