Wavelength Division Multiplexing (WDM) Couplers

Abstract

AbstractThere have been rapid advances in multiplexer and demultiplexer development driven bythe promises of WDM to increase the information- carrying capacity of optical fibers. The design of WDM components selected for a particular system depends on system pa- ameters suchas number of channels, direction of channels, channel loss budget, bandwidth, and source type. Multiplexers and demultiplexers can be categorized according to the optical techniqueused to make the couplers wavelength selective: filters or dispersive elements. Opticaldesign examples show that filter type couplers are best for a small number of channels (3 -4)while dispersive type couplers are better for larger numbers of channels. System designexamples are given for three types of systems with up to eight channels. Experimentalresults on WDM multiplexers,' demultiplexers, and bidirectional couplers are given. Couplersoptimized for operation in a single direction have been demonstrated with channel insertionlosses <2 dB and crosstalk <40 dB between channels. Couplers for bidirectional operationare shown to have higher losses. The severe effect on system crosstalk performance of out -of -band source emission is discussed.Wavelength Division Multiplexing (WDM) CouplersThere have been rapid advances in wavelength division multiplexing (WDM) optical couplersdriven by the promise of WDM to greatly increase the information- carrying capacity ofoptical fibers. The design of WDM couplers for a particular system depends on system para-meters such as number of channels, data rate, channel loss budget, and bidirectional use of