| 摘要 |
PURPOSE:To make a device small-sized by forming plural optical waveguides consisting of optical waveguides for incidence/exit on the same substrate and joining alternately laminated wavelength filter and spacer to end faces of optical waveguides and guiding the reflected light from the wavelength filter and that from the end face of the spacer to optical waveguides for exit different from each other. CONSTITUTION:An optical waveguide 5 consists of an optical waveguide 5a for incidence and plural optical waveguides 5b and 5c for exit, and a wavelength filter 8 is provided in such position that the light guided by the optical waveguide 5a for incidence is reflected on the wavelength filter 8 and is guided by the optical waveguide 5b for exit, and the thickness of a spacer 9 is so set that the light transmitted through the wavelength filter 8 is reflected on the end face of the spacer 9 and is guided by the optical waveguide 5c for exit. A filter which reflects the light having a wavelength lambda1 but permits the light having wavelengths lambda2 and lambda3 to pass through is used as the wavelength filter 8 in this wavelength branching device; and thereby, only the light having the wavelength lambda1 is quided by the waveguide 5b, and the light which does not include the wavelength lambda1 but has wavelengths lambda2 and lambda3 is guided by the waveguide 5c, and a substrate 6 is made small-sized to the outmost limit. |
