Abstract: The present invention relates to a method of making a diffraction grating device, in which an optical waveguide is irradiated, by way of a phase grating, with light capable of inducing a refractive index modulation in an optical waveguide region of the optical waveguide so as to form a diffraction grating in the optical waveguide region. In the present invention, when modulating the refractive index of the optical waveguide region of an optical fiber, the intensity of refractive index modulation inducing light emitted from a laser light source so as to irradiate the phase grating is adjusted according to individual positions on the phase grating. Alternatively, the scanning speed of a mirror scanned by a stage is adjusted according to the individual positions on the phase grating. Here, the amount of irradiation of refractive index modulation inducing light at each position on the phase grating is adjusted so as to cancel the diffraction efficiency distribution of phase grating.

Abstract: The method of making a diffraction grating device in accordance with the present invention comprises the steps of preparing an optical waveguide having an optical waveguide region doped with an additive adapted to generate a refractive index change upon irradiation with refractive index change inducing light having a predetermined wavelength, and a phase grating having a predetermined projection and depression pattern; separating the optical waveguide and the phase grating from each other by a distance yielding a predetermined optical path difference between zero-order transmitted light and second-order diffracted light of the refractive index change inducing light such that a modulation intensity of interference light between the zero-order transmitted light and second-order diffracted light becomes 85% or less of that obtained when no optical path difference exists between the zero-order transmitted light and second-order diffracted light; and making the refractive index change inducing light incident on th

Abstract: The present invention relates to a method of making a diffraction grating device, in which an optical waveguide is irradiated, by way of a phase grating, with light capable of inducing a refractive index modulation in an optical waveguide region of the optical waveguide so as to form a diffraction grating in the optical waveguide region. In the present invention, when modulating the refractive index of the optical waveguide region of an optical fiber, the intensity of refractive index modulation inducing light emitted from a laser light source so as to irradiate the phase grating is adjusted according to individual positions on the phase grating. Alternatively, the scanning speed of a mirror scanned by a stage is adjusted according to the individual positions on the phase grating. Here, the amount of irradiation of refractive index modulation inducing light at each position on the phase grating is adjusted so as to cancel the diffraction efficiency distribution of phase grating.

Abstract: According to the present invention, a periodically perturbation part which serves as a refractive index modulated part is provided in a part of the optical waveguide of an optical fiber or the like in the longitudinal direction thereof, a line perpendicular to a level plane of this periodically perturbation part is tilted with respect to the optical axis X of the optical waveguide, and the plane defined by this optical axis X and a line A intersecting the optical axis X, that is, the deflection angle plane M is made, by twisting or the like, to include a portion that varies depending on the position of the optical waveguide in the longitudinal direction thereof.