Energy-Efficient Chromatic Dispersion Compensation for Coherent Fiber-Optic Receivers

DSP-based chromatic dispersion compensation accounts for a large part of the overall power dissipation in fiber-optic receiver ASICs. We have implemented and evaluated compensation filters based different design methods using a MATLAB-based coherent fiber-optic system model in respect to compensation performance, filter length, and fixed-point aspects. Possible power savings when taking into account that the pulse-shaped, over-sampled signal is band-limited when designing the filters were investigated. Different complex FIR filter topologies, including configurable filters, have been implemented and evaluated in terms of power dissipation. MCMbased and fast-FIR-based approaches were found to significantly reduce power consumption in comparison to a transposed FIR filter. The half-band filter allows for a significant reduction in power consumption, given that the signal is band-limited to [-π/2–π/2]. Implementing reconfigurability was found to incur an additional power dissipation of 50%.