| 摘要 |
PROBLEM TO BE SOLVED: To provide the variable wavelength selection filter that selects two kinds of wavelengths with a high density by combining the prism, on which a filter is vapor deposited, and a liquid crystal etalon. SOLUTION: A prism 7, on which a wavelength selectable transmissive/ reflecting type filter 8 is vapor deposited, is mounted on one side surface of a pair of glass substrates 5 and 6 which are facing to each other. Two liquid crystal etalon E1 and E2 are arranged along the facing surfaces of the substrates 5 and 6. The transmissive light beams, having wavelength multiplexed signals which are made incident on the filter 8 from an incident side collimeter lens 3, are made incident on one of etalon E2 and the reflected light beams are reflected by the prism 7 and made incident on the E1 to conduct wavelength selections. |
