Patent ID: 9036967
Filing Date: 2015-05-19
Classification: G01J,G02B

Abstract:
1. An optical filter insensitive to polarisation centred on a wavelength (λ 0 ) measured in a vacuum, comprising: a first waveguide supporting a first propagation mode; a second waveguide supporting a second propagation mode; a first grating formed in or on the surface of the first waveguide, the first grating being periodic of period d a second grating formed in or on the surface of the second waveguide, the second grating being periodic of period d wherein the first and the second gratings are arranged one above another and are such that a third axis Oz is normal to the surface of the waveguides and that the first axis Ox and the second axis Ox′ form an angle ξ different than +−π/2 radians such that when the first grating is illuminated by a light beam the first and second propagation modes are excited and their fields are orthogonal for an angle of incidence of the light beam, and the first and second gratings have respective diffraction orders n and m, wherein the respective directions of propagation V with θ and Φ being polar and azimuth angles, respectively, and λ being the wavelength of the light beam, and wherein the condition of excitation of the first mode via the first grating is ∥V