Wavelength-tuneable add/drop multiplexer using broadband transmission filters and a narrowband reflection filter

摘要

We present an optical add/drop multiplexing device utilising a pair of broadband transmission filters and a narrowband reflection filter, designed for operation in a dense wavelength-division multiplexing network. Evanescent field coupling in an optical fibre-based cladding-mode coupler allow broadband light to be transferred between two fibres containing non-uniform long-period fibre gratings. An erbium-doped fibre amplifier was used to restore the power level of the output signal obtained from the cladding-mode coupler, to its original level. A tuneable Bragg grating is used to select a specific wavelength channel from the broadband light routed through the cladding-mode coupler, and is able to work over a linear tuning range of 5.3 nm, covering . 13% of the C-band.