Waveguide interleaving filters

Abstract

Optical Interleaving filters are attractive components in Wavelength Division Multi/Demultiplexing (WDM) systems especially narrower than 100GHz channel spacing system. Several types of interleaving filters have been proposed and realized. An interleaving filter is required to have the Box-like characteristics such as the periodic response, flat-passband, low insertion loss and low crosstalk. In addition, low chromatic dispersion (CD) is indispensable for Dense WDM (DWDM) systems. We focus on planar lightwave circuit (PLC) interleaving filters. In this paper, we present interleaving filters with a tandem configuration of Fourier transform-based Mach-Zehnder Interferometers (MZIs). The circuit using PLC technique is fabricated with high index contrast waveguides of ? 1.5%. We also have demonstrated integrated 1x4 (25-100GHz,50-200GHz) interleaving filters and arrayed waveguide gratings (AWGs) with 200GHz-channel spacing suitable for interleaving WDM system.

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

“…Most interleavers are based on Michelson interferometers, Mach-Zehnder interferometer (MZI) or birefringent filter (BF) principles, and they are implemented in bulk optics, all-fiber, or integrated optics technologies [3], [4]. In these configurations, different phase-dispersion elements, such as ring resonators (RRs), Gires-Tournoise etalons, and resonant cavities, may be used to improve their boxlike characteristic [5], [6].…”

“…But those solutions increase considerably the interleaver's chromatic dispersion (CD) and its sensitivity to manufacturing tolerances. Interleavers can also be implemented by using Fabry-Perot filters [7], Bragg diffraction gratings, and arrayed waveguide gratings (AWG) [4].…”

“…Fourier-series-based method uses a lattice structure with delay lines multiples of a unit value [4]. This method uses M-simultaneous equations to determine an M-order filter structure to fit an ideal transfer function shape.…”

10 GHz femtosecond pulse interleaver in planar waveguide technology

“…To satisfy the growing demand for more information capacity, fiber coupled and planar waveguide optical interleavers have been utilized to increase the channel spacing. These interleaving filters were primarily designed for wide-bandwidth pass-bands by cascading multiple stages and optimizing the coupling coefficient ratios at each individual interleaver stage for operating frequencies around 50-100 GHz [10][11][12][13]. A good overview over different interleaver implementations can be found in Cao [14] and Kawachi [15], who outlines the various silica waveguide technology components.…”