| 摘要 |
PURPOSE:To measure the power demultiplexing ratio, light loss, etc., of individual demultiplexing or multiplexing elements in an optical circuit independently without any destruction by detecting characteristics at individual demultiplexing or multiplexing points from the difference in propagation time among plural different optical paths by using coherent light. CONSTITUTION:The coherent light 1 is branched 2-1 into two pieces of luminous flux, which are supplied to a multiplexer demultiplexer 4 and an optical frequency converter 8 through polarized light converting elements 3-1 and 3-2 and the polarized states of both light beams are made coincident with each other. A frequency converter 8 shifts incident light by a constant angular frequency OMEGA and outputs it as reference light to perform variable control 9 over its optical path length. A half-mirror 22 multiplexes the output light of the multiplexer demultiplexer 4 and the reference light whose optical path length is varied 9 and an interference signal is photodetected 10 and detected 11 to store the signal amplitude of a OMEGA component as a function of the delay distance l of an optical path length varying element 9. Consequently,the power branching ratio and loss of the two-input, two-output optical multiplexer demultiplexer are measured by this method independently without destruction. |
