To provide an optical waveguide type diffraction grating element and optical parts in which optical characteristics are adjusted.
When stress is applied to an optical waveguide type diffraction grating element 100, the stress to an optical fiber 110 at that location becomes large as the cross-sectional area of a cover member 120 at the position on an optical axis direction becomes small and the rate of variation of refractive index modulation grating gaps at that position become large. In other words, when the grating gaps of the refractive index modulation of the element 100 is uniform along the longitudinal direction while no stress is applied, a change occurs in the longitudinal direction by adding tension. The smaller the cross-sectional are of the member 120 becomes, the longer the grating gaps of refractive index modulation becomes.
SHIBATA TOSHIKAZU
INOUE SUSUMU
