Wavelength tunable reflector and methods

摘要

A novel wavelength tunable reflector (10) and method are demonstrated. The wavelength tunable reflector comprises a birefringent material that may be a cholesteric liquid crystal with a helical structure that forms a phase grating. An optical transmission medium (OTM) (20) is juxtaposed to the birefringent material (80) such that a component of an evanescent field of an optical signal propagating through the OTM (20) is perturbed by the phase grating. The period of the grating is tuned in at least one portion of the birefringent material by applying AC voltages across respective portion(s) of the birefringent material (80) such that one or more channel of the optical signal, each having a specific center wavelength, are reflected. The wavelength tunable reflector is adapted for other applications such as wavelength selective add/drop multiplexers, wavelength selective variable optical attenuators, broadband spectrum equalization filters, gain flattening filters for optical amplifiers and re-configurable dispersion compensators. <IMAGE>