| 摘要 |
<P>PROBLEM TO BE SOLVED: To surely prevent the trouble that an etchant suitable for etching an SiO<SB>2</SB>film laminated in an anisotropic crystal plate made of crystal or the like etches even the anisotropic crystal plate having the same composition as the SiO<SB>2</SB>film to bring about over-etching when working the SiO<SB>2</SB>film into a grating by etching in a process of manufacturing a wavelength plate grating element obtained by joining the anisotropic crystal plate functioning as a wavelength plate and a diffraction grating made of SiO<SB>2</SB>. <P>SOLUTION: The wavelength plate grating element is provided with a wavelength plate 32 made of a crystal plate, an intermediate layer 33 laminated on one side of the wavelength plate, and a diffraction grating 34 which is formed on the intermediate layer and is made of SiO<SB>2</SB>, and the intermediate layer is made of a material which has a refractive index approximating that of SiO<SB>2</SB>and is not etched by the etchant suitable for etching the SiO<SB>2</SB>. <P>COPYRIGHT: (C)2004,JPO |
