Study Of Comb Spectra Applied To Large Capacity Optical Transmission System

Ultra-high speed, large capacity has become the main goals of information transmission, companies and research institutions have started the research of optical transmission system,400G/1T system become the research focus. For beyond100G research scheme, using ultra wide band (super-channels) has become a popular solution scheme, comb spectra is one of the key technologies. In this paper, after investigation of several kinds of ultra wide-band generation of optical comb, it focuses on multi-carrier generation based on RFS (Re-circulating Frequency Shifter) for Tbit transmission scheme. Its essence is to use a light IQ modulator to produce spectrum move. Then the original signal is coupled with the move signal over and over again after the loop to get multiple carriers, forming optical comb.Generation of the optical comb with great stability and flatness is the problem we will focus. Based on the detailed analysis of the related devices, this paper is established on the cyclic frequency shift based on single sideband modulator multicarrier of the existing theory and experimental research, combined with basic principle of the devices in the multi-carrier generation scheme, and the polarization characteristics, investigate the simulation scheme and study the corresponding solution. Main work has the following several parts:(1) The development of optical fiber transmission and multi-carrier source development’s and research background and significance are expressed.(2) Brief introduction of the research situation and several methods of comb generation, and the relevant theoretical knowledge has been analyzed and then the principle of the main related devices, including all kinds of modulator, EDFA, polarization theory and the polarization controller are researched.(3) Set up the multicarrier system simulation platform single based on sideband modulator frequency shift ideally, to get the third order harmonic component as the main crosstalk of transfer function, optimize the system solutions, to establish the simulation platform, improve the signal-to-noise ratio and the number of generated light output carrier, finally to generate stable flat50optical comb spectra. And analyze the actual situation may exist will have various influences on the theoretical analysis and simulation, including the unbalanced RF signal, transfer function and so on.(4) Set up the experimental system to verify the theoretical analysis. Variable values’s change can cause different experimental results, the final purpose is to achieve a stable flat multicarrier output.To sum up, this paper made a systematic research on the T bit transmission system’multicarrier light source based on single sideband modulator RFS. Starting from the mathematical model of multicarrier light source, to analyze the factors affecting the stability of light source, some important conclusions are achieved, meanwhile and through the experiment, the correctness of the theoretical analysis is verified.