Chromatic Dispersion Compensation Algorithm Simulation&FPGA Implementation For Optical Coherent Detection

In recent years, digital signal processing (DSP) based coherent detectiontechnology has aroused widespread concern. On one hand, the application of thistechnology can lead to higher spectral efficiency, thereby enhancing thesingle-channel transmission capacity; On the other hand, DSP-based coherentdetection techniques such as chromatic dispersion (CD), polarization mode dispersion(PMD), nonlinear effects (Non-Linear) and other related fiber damage compensationof the electric field greatly reduces the system cost. CD compensation technology isone of the most important technologies in the coherent detection. Along with the highspeed upgrade of the network transmission rate, the CD compensation technique hasbecome increasingly important. At the same time, the research of CD compensationalgorithm and hardware implementation also increases.At the beginning, the analysis and simulation of linear equalization for opticalfiber channel are carried out, covering the influence of filter length for chromaticdispersion compensation. The impact of the filter length of the chromatic dispersioncompensation are also analyzed and discussed.A polarization multiplexed QPSK coherent communication system is designedby Optisystem and MALAB, which shows in detail the operational processes of thecoherent detection technique based on digital signal processing.Chromatic dispersion compensation algorithm implementation is the focus ofthis article. For the problem of algorithm in the system model between hardwareimplementation barrier in optical transmission systems, we introduce model-basedFPGA design flow, which have been gradually been respected in recent years. At thesame time, we also introduce the traditional FPGA design flow for comparison. Incontrast, the model-based FPGA design flow allows the designers to pay moreattention to system level, shorten the design cycle. Later, constraints for algorithms indigital receivers for coherent optical communication are analyzed and discussed; wepoint out that the algorithm should support parallel processing, and achieve higherhardware efficiency. In the end, on the problem of CD compensation algorithm hardware implementation, this paper presents a improved a complex FIR filterstructure, in which the performance of multipliers improve nearly12%, and deviceresource usage has declined by14%.