Synthesis of Asymmetric Flat-Top Birefringent Interleaver Based on Digital Filter Design and Genetic Algorithm

A flexible and fast synthesis method for designing asymmetric interleavers with flat-top, low dispersion, adjustable isolation, and bandwidths at both outputs is proposed. Interleavers are designed on birefringent technology allowing linear-phase designs.
$Z$
-transform properties and digital filter design techniques are used for designing interleavers under a set of specifications. At a second level, a genetic algorithm optimization approach allows improving the interleaver design adjusting the minimum isolation, at both outputs, below
$-$
43 dB and the stop bandwidths to specific normalized values of
$\pm$
0.15 and
$\pm$
0.3, with zero dispersion at one output. Improvement of the interleaver order and dispersion below
$\pm$
50 ps/nm at both outputs are also reported.