All-fibre channel selective matrices for high density wavelength division multiplexed systems

Describes the use of all-fibre tunable wavelength selective devices with very narrow pass-band response for selecting channels in high density WDM systems. The all-fibre tunable filter structures are realised by concatenating a number of wavelength selective couplers each with a specific spectral response. The effective overall response at the matrix output can be shaped into narrow pass-band characteristics by careful choice of the matrix couplers. Furthermore, the authors describe the process whereby this matrix can be developed, using electrical wavelength tunable couplers which would provide a tunable channel selective property. Such devices represent an alternative to coherent multichannel systems avoiding the requirement for a relatively high cost narrow linewidth local oscillator laser. They also describe as an example the use of such a tunable WDM channel selector in high density WDM system as well as in coherent multichannel applications using experimental results of narrow-band tunable coupler and matrices