Disclosed is a tunable optical filter which may be used in telecommunications systems. The filter comprises a single mode optical waveguide containing a grating. The resonance wavelength of the filter is changed by changing the boundary condition at the interface between the cladding layer and an additional...http://www.google.com/patents/US6498877?utm_source=gb-gplus-sharePatent US6498877 - Tunable optical fiber bragg and long period grating
