Optical multiplexer/demultiplexer using resonant grating filters

Abstract

A wavelength division multiplex/demultiplexer (WDM) has a plurality of narrow-band zeroth order resonant grating filters (10a-10e) to multiplex or demultiplex multiple wavelengths that have very close channel spacing. In one embodiment, a plurality of these filters (10a14 10e) are assembled in a block (20) in parallel and at an angle to a propagation axis to reflect signals for a plurality of discrete frequency channels. The block spacing material (21) can be liquid or solid. In another embodiment, the angular orientation of the resonant grating filters (10f-10g) is varied slightly to provide reflected signals for the plurality of discrete frequency channels. Crosstalk between channels can be reduced by reflecting each signal three times. Individual filters can be of binary structure or a sinusoidal grating (16) and can be made using thin film techniques.

Dependencies are inferred from the claim text.