| 摘要 |
PROBLEM TO BE SOLVED: To make a device more small-sized on the whole by making the device not only small in diameter, but also short. SOLUTION: A birefringent element 10 for polarized light demultiplexing, a birefringent element 12 for optical path shifting, and a birefringent element 14 for polarized wave multiplexing are arranged and polarized wave rotation control means 16 and 18 are interposed among the birefringent elements; and a 1-input port part composed of a single-core ferrule 29 and a lens 30 is installed at one end part of them and a 2-output port part composed of a two-core ferrule 34 and a common lens 36 is installed at the opposite-side end part. The polarized wave rotation control means comprise combinations of variable Faraday rotators 20 and 24 and 1/2-wavelength plates 21 and 22, and 25 and 26 and rotate one polarization direction by 90°by controlling applied magnetic fields. An optical path changing prism 38 which changes the angles of one or both light beams is interposed between the optical path shifting birefringent element and polarized wave multiplexing birefringent element and output ports are selected according to a differences in light beam direction. COPYRIGHT: (C)2004,JPO
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