Optimal Least-Squares FIR Digital Filters for Compensation of Chromatic Dispersion in Digital Coherent Optical Receivers

• Published in: Journal of lightwave technology 2014-04, Vol.32 (8), p.1449-1456
• Main Authors: Eghbali, Amir, Johansson, Hakan, Gustafsson, Oscar, Savory, Seb J.
• Format: Article
• Language: English
• Subjects: Applied sciences; AWGN channels; Bit error rate; Chromatic dispersion (CD); Circuit properties; Delays; Detection, estimation, filtering, equalization, prediction; digital filter; Electric, optical and optoelectronic circuits; Electronics; Exact sciences and technology; fiber optics; Finite impulse response filters; Information, signal and communications theory; Integrated optics. Optical fibers and wave guides; Interpolation; Modulation; Optical and optoelectronic circuits; optimal least-squares (LS) FIR filter; Pulse shaping methods; Signal and communications theory; Signal, noise; TECHNOLOGY; TEKNIKVETENSKAP; Telecommunications and information theory
• ISSN: 0733-8724; 1558-2213; 1558-2213
• DOI: 10.1109/JLT.2014.2307916

This paper proposes optimal finite-length impulse response (FIR) digital filters, in the least-squares (LS) sense, for compensation of chromatic dispersion (CD) in digital coherent optical receivers. The proposed filters are based on the convex minimization of the energy of the complex error between the frequency responses of the actual CD compensation filter and the ideal CD compensation filter. The paper utilizes the fact that pulse shaping filters limit the effective bandwidth of the signal. Then, the filter design for CD compensation needs to be performed over a smaller frequency range, as compared to the whole frequency band in the existing CD compensation methods. By means of design examples, we show that our proposed optimal LS FIR CD compensation filters outperform the existing filters in terms of performance, implementation complexity, and delay.