| 摘要 |
PURPOSE:To reduce reflected return light by arranging and fixing the incidence surface of a polarized light separating means and a GRIN lens end surface which faces it, and the incidence surface of a polarized light multiplexing means and a GRIN lens end surface which faces it while gaps of air are left. CONSTITUTION:Light is made incident from a quartz fiber 11a, made parallel by the GRIN lens 4a, and split by a splitter 2 into P-polarized light and S- polarized light, which are passed through a liquid crystal cell 11. When no voltage is applied to the cell 1, the cell converts the P-polarized light into S- polarized light and S-polarized light into P-polarized light, a multiplexer 3 multiplexes them, and its output is projected on a fiber 11c through the GRIN lens 4c. The incident light to a fiber 11b is projected on a fiber 11d. When the voltage is applied to the cell 1 through a DC/AC converter 12, the cell passing light is not polarized and projected on the fiber 11c from 11b and the optical path is switched according to whether the voltage is applied or not. The GRIN lenses 4a - 4d, polarized light splitter 2, and polarized light multiplexer 3 are coupled through an air gap of about 1mm, so the light wavelength is much larger than about 1.3mum and there is a little variation in the quantity of reflected light with gap variation with temperature. |
