High-Speed Frequency-Domain CDC Filters with Reconfigurable Filter Length

Sammanfattning

To meet the requirements for real-time operation and flexibility in chromatic disper-sion compensation (CDC) for high-speed coherent optical communication systems, tra-ditional fixed-structure frequency-domain CDC filters suffer from limited adaptability aswell as high power and hardware cost. This thesis proposes a high-speed reconfigurable-length frequency-domain CDC filter architecture based on a cascaded structure consistingof a fixed 192-point P-FFT and a reconfigurable C-FFT in C = 2/4/8. Combined withoverlap-save streaming processing, the architecture enables real-time chromatic disper-sion compensation at a sampling rate of 60 GSa/s with 128-way parallel input. The workcompletes the RTL design and implementation of the reconfigurable data-routing unit,reconfigurable FFT, and compensation modules, and evaluates the hardware through syn-thesis and simulation in a 28-nm CMOS process at 0.70 V and 553 MHz. The resultsshow that the proposed architecture operates correctly, supports dynamic adjustment ofthe filter length without interrupting the data stream, and achieves significantly reducedreconfigurability overhead in high-parallelism modes. At C = 8 the additional poweroverhead relative to the fixed architecture is only 33.52%, while the proposed design alsoshows a clear area advantage. The architecture provides a practical solution that balanceshigh-speed processing capability, low power consumption, and reconfigurability for ASICdesign in high-speed coherent optical communication systems.