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Chromatic dispersion equalization FIR filter design based on discrete least-squares approximation.
Optics Express
|July 16, 2021
Summary
This study revisits chromatic dispersion (CD) equalization, proposing a novel finite impulse response (FIR) filter design using discrete least-squares approximation. This method simplifies CD equalization in optical coherent receivers by relying solely on Fourier transforms.
Area of Science:
- Optical Communications
- Digital Signal Processing
- Filter Design
Background:
- Chromatic dispersion (CD) equalization is crucial for digital signal processing (DSP) in optical coherent receivers.
- Conventional impulse-invariant methods for CD equalization filter design have limitations.
Purpose of the Study:
- To propose an improved method for designing CD equalization filters.
- To develop a finite impulse response (FIR) filter based on discrete least-squares (LS) approximation.
- To demonstrate the flexibility of the proposed method for joint matched filtering and CD equalization.
Main Methods:
- Revisiting and improving the conventional impulse-invariant method by reinterpreting it as a Fourier series.
- Proposing a discrete LS approximation for designing the CD equalization FIR filter.
- Utilizing Fourier transforms for filter design, avoiding complex numerical evaluations.
Main Results:
- The proposed discrete LS approximation method simplifies CD equalization filter design.
- The method avoids the numerical evaluation of nontrivial functions.
- Demonstrated the filter design's flexibility for joint matched filtering and CD equalization.
Conclusions:
- The proposed discrete LS approximation offers an efficient and flexible approach to CD equalization filter design.
- The method simplifies the DSP chain in optical coherent receivers.
- The approach is suitable for advanced applications like joint matched filtering and CD equalization.
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