POLARIZATION-INSENSITIVE OPTICAL FILTER WHICH HAS RESONANT GRATINGS AND IS ADJUSTABLE ACCORDING TO THE INCIDENCE ANGLE

摘要

The invention relates to a polarization-insensitive optical filter centered on a wavelength (?0) measured in vacuum, comprising: first and second waveguides (21, 21') each having a propagation mode; a first grating (11) formed in or on the surface of the first waveguide (21), the first grating being periodical at least along a first axis Ox defining a first orthonormal base Oxyz; a second grating (11') formed in or on the surface of the second waveguide (21), the second grating being periodical at least along a second axis Oxy' defining a second orthonormal base Ox'y'z; wherein the first and second gratings are provided above each other and are such that the first axis Ox and the second axis Ox' define an angle ? different from ± p /2 radians so that, when the first grating is illuminated by a light beam, the first and second propagation modes are excited and have orthogonal fields for a predetermined angle of incidence of the light beam.