| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a method and apparatus for adjusting an optical path length in an optical path, which adjusts the optical path length with low loss by changing the optical length, while changing by a polarization controller, the branch ratio of a duplex optical path constituted of a polarization maintaining optical fiber formed between a pair of input polarization separation coupler and output polarization synthetic coupler in a detour line. <P>SOLUTION: The apparatus for adjusting the optical path length in the optical path is equipped with: the duplex optical path constituted of the polarization maintaining optical fiber 22 formed between a pair of input polarization separation coupler 13 and output polarization synthetic coupler 18; the polarization controller 12 connected to the input port side of the input polarization separation coupler 13 so as to change the branch ratio of the duplex optical path; optical fiber changeover devices 17, 19 for changing by prescribed length step, the optical path lengths to be arranged in the respective lines of the duplex optical path; and a continuous optical path length adjusting device 21 arranged at least one of the lines of the duplex optical path so as to continuously adjust the optical path length within a range including the prescribed length. <P>COPYRIGHT: (C)2011,JPO&INPIT |
