Equalization of Gaussian-Like Spectra via Optical Lattice Filters With Symmetric-Feedback Structure

This paper presents a scheme for equalizing Gaussian-like spectra by using all-fiber lattice filters with a symmetric feedback structure. With the proposed design strategy and feedback structure, the output power of Gaussian-like spectra is maximized, and the designed equalization filter can flatten the Gaussian-like spectra in the maximally flat sense while satisfying specified spectrum performance. The design scheme is able to efficiently and systematically determine the optimal coefficients of the lattice filter through a recursion algorithm. As an illustrative example, the proposed scheme is applied to the design of an all-fiber equalization filter to flatten the output spectrum of a superluminescence light-emitting diode. Simulation and experimental results are carried out to verify the theoretical analysis