Abstract

Interleavers enable the practical implementation of dense wavelength division multiplexing (DWDM) systems by transforming the task of separating or combining a single set of very closely spaced channels into separating or combining multiple sets of widely spaced channels. Regardless of the approach, be it thin-film filter, fiber-Bragg grating, arrayed waveguide grating, Echelle grating, or bulk diffraction grating, mux/demux modules can be less expensive and easier to make if the channel spacing is wide relative to the required passband width. Interleavers allow the application of these wide channel spacing solutions to the harder problem of more closely spaced channels. Most interleaver designs are based on cascaded Mach-Zehnder (M-Z) interferometers. Researchers have constructed these cascaded M-Z interleavers out of fused fibers and planar lightwave circuits for example.¹⁻² Other, non-M-Z and hybrid-M-Z approaches exist as well.³

© 2002 Optical Society of America