Patent ID: 6744949
Filing Date: 2004-06-01
Classification: G02B

Abstract:
An optical wavelength filter comprising:an optical fiber or an optical waveguide, having a core and cladding, with at least one of said core and cladding comprising a structure having a periodically varying diffraction coefficient extending along a direction of propagation of light through said filter, and with at least one parameter of said periodically varying diffraction coefficient structure continuously varying along said direction of propagation for creating a range of reflection wavelengths of said filter, wherein said periodically varying diffraction coefficient structure comprises at least one interruption portion interrupting said continuous variation, thereby creating a corresponding passband of said filter, with said passband located at a predetermined position within said range of reflection wavelengths, said periodically varying diffraction coefficient structure has a fixed pitch, said parameter which continuously varies is an average value of a diffraction coefficient of said periodically varying diffraction coefficient structure, and said at least one interruption portion comprises a portion of said periodically varying diffraction coefficient structure at which a transition occurs from a first average value of a diffraction coefficient to a second average value of a diffraction coefficient.