| 摘要 |
PROBLEM TO BE SOLVED: To provide a method for reducing the excessive loss of the array waveguide grating whose wavelength characteristic is not varied to variations of an ambient temperature. SOLUTION: The widening of light in a groove part is controlled and the excessive loss owing to the addition of the groove is reduced by applying either of the following changes or the change combined thereof to a wedge type groove part 4 provided in the array waveguide part 3 of an array waveguide grating or to the peripheral quartz waveguide part. A photosensitive material is used as the material embedded into the groove part 4 wherein a refractive index temperature coefficient is negative, the difference of the refractive index is also provided in the groove part utilizing the photosensitivity, and whereby an optical waveguide is formed in the traverse direction or in both longitudinal and traverse directions. A material having a high refractive index is used as the material embedded into the groove part 4 whose refractive index temperature coefficient is negative, and the widening angle when light is made incident on the groove part is reduced. The traverse width of the quartz waveguide in the front and the back of the groove part is enlarged, and the widening angle is reduced when light is made incident on the groove part. |
