Active diffraction grating

摘要

When a voltage is applied to plural spot electrodes selected from the spot electrodes arranged in the matrix form and the light incident on the two-dimensional plane waveguide is reflected by at least two parallel lines, the refractive index of the optical waveguide is partly changed so that the wavelength of the light, the angle of the two lines to the incident light and the distance between the lines satisfy the Bragg reflection condition.