OFDM-based Variable Bandwidth Optical Network Key Technology Research

The industry of internet and telecommunication have rapid development in recentyears. Especially, a lot of new information services rise rapidly, such as mobile Internet,cloud computing and the integration of the three networks, make the optical networkresources become tighter. Therefore, higher quality dynamic management are demand.In addition to the100G/400G networks, the high-speed end-to-end transmissiontechnology have been put on the agenda. In the same time, the more flexible andnon-standard bandwidth planning is also into the research scope.This article discusses the basic concepts of variable bandwidth optical network,current research status and the key enabling technology. As a signal modulation formatand a frequency domain multiplexing scheme, all-optical OFDM technology has itsunique technical advantages. For example: an OFDM signal has high spectral efficiency,in the OFDM transceiver, signal processing can use of highly efficient DFT/IDFTalgorithms. The difference of all-optical OFDM and non-all-optical OFDM is whethersignal processing is in the optical domain or in the electrical domain.The follow chapters have dealt with the derivation of the mathematical principlesof OFDM, explain the relationship of All-optical OFDM and discrete Fourier transform,introduce two kind of all-optical OFDM scheme: the multi-carrier multiplexing schemeand the sampling of ultrashort light pulses scheme. In the third chapter, we analysis thetheory of all-optical DFT/IDFT structure with eight carriers, and optimize the structurebased on optocoupler. In this paper we use VPI software to proved the availability ofthis structure, and the experiments show its correctness.In Chapter four of this article, several new multi-carrier sources based on aMach-Zehnder modulator have been researched by using the simulation software,including: cascade multi-carrier phase modulator generator, multi-carrier generatordriven by dual-drive Mach-Zehnder modulator (DD-MZM), and the multi-carriergenerator based on the the RFS principle.Finally, this article study the ROADM which is the key composition of variablebandwidth optical network and its important part: variable bandwidth wavelength selective switch (WSS). Combining the work during the research stage, the articleproduce the features of the project, show the test performance of the finished board, andproposed an transmitter architecture,which is adapts to the novel variable bandwidthoptical network.