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

Abstract

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 À43 dB and the stop bandwidths to specific normalized values of AE0.15 and AE0.3, with zero dispersion at one output. Improvement of the interleaver order and dispersion below AE50 ps/nm at both outputs are also reported.

Fast iterative algorithms for birefringent filter design

“…A backward recursion of the transfer matrix is used to calculate the parameters of an optical filter that has an impulse response with complex coefficients. In [7] a general synthesis method for designing asymmetric flat-top birefringent interleavers is reported using a combination of digital signal processing approach and computational optimization by GAs. The birefringent filter structure may be synthesized using a different technology based on coherent optical delay-line circuit with a two-port lattice-form configuration [19] where arbitrary filter characteristics corresponding to nth-order complex FIR digital filters can be realized by n cascaded two-port lattice-form optical delay-line circuits.…”

Recent Advances in Wavelength-Division-Multiplexing Plastic Optical Fiber Technologies

“…Literature provides many optical filtering and interleaving devices. Some filters are based on birefringent structures such as the Lyot and Solc filters due to their low dispersion, high reliability, easy fabrication process and low cost [75], with recent applications in VIS for POF networks [69,74]. However, these solutions mainly operate in DWDM systems (infrared range).…”

“…Birefringent filters can be designed by using optimization methods or in the Z-transform domain, by using their relation with FIR (Finite Impulse Response) filters. A detailed method for transform FIR filters into birefringent filters can be found in [75]. For example, an arbitrary birefringent filter of seven retarder plates, obtained from a 7 th order FIR filter, is presented in Fig.…”

“…It could even be designed to have a narrow bandpass. Birefringent structures are a versatile solution for designing devices for POF WDM networks due to their reconfiguration capacity, since they can be easily manufactured with LC technology, and flexibility, since any FIR filters synthesis method can be used [75]. It should be mentioned that demultiplexer devices may be easily built up by combining the switches and filter schemes described in former sections or by using filter plus the addition of POF splitting devices.…”

Broadband 1×2 liquid crystal router with low thermal dependence for polymer optical fiber networks

“…The birefringence wavelength dependence, Δn(λ), is a very important parameter for designing broadband devices with stacked structures [25,29]. In this work, Δn(λ) is represented with the extended Cauchy model [22], which is expressed as α H , with respect to the x-axis (see Fig.…”