| 摘要 |
PURPOSE:To prevent the degradation in filter characteristics by using two sheets of filter elements which are disposed on both surfaces of a triangular prism and reflect light of different wavelengths, respectively. CONSTITUTION:An interference filter which reflects light of a wavelength lambda1 is formed on one surface of a thin triangular prism 5 of a vertical angle alpha and an interference filter which reflects the light of a wavelength lambda2 is formed on the other face opposite thereto in such a way that the light is reflected in the same direction and therefore if the multiplie light waves of the wavelengths lambda1 and lambda2 are projected from an input optical fiber 71, said waves are collimated by a projecting lens 8, and are made incident to the above-mentioned optical fiber, by which the light of the wavelength lambda1 is reflected as shown by chain lines and the light of the wavelength lambda2 is branched as shown by dotted lines, respectively, and these beams of the light are made incident to the lens 8 at desired angles. The wavelengths lambda1, lambda2 are condensed by the lens 8 and are made respectively incident to output fibers 72, 73, whereby said wavelengths are transmitted. |
