| 摘要 |
PROBLEM TO BE SOLVED: To improve measurement precision by inexpensively constituting a lens, a light-receiving element and a detection circuit, eliminating the secular change of measurement sensitivity between two inputs, reducing a loss occurring in a two input fiber and reducing polarization depending loss fluctuation in a two input fiber-type light-receiving device. SOLUTION: The two input fiber-type light variation device is provided with the two input fiber 4 generated by fusion-extending two optical fibers and cutting them in the center of a fusion extending part, the lens 6 converging light which is made incident on from the plug 5a or plug 5b of the two input fiber 4 into an almost same place, the light-receiving element 7 receiving light converged by the lens 6 and the detection circuit 8 detecting the optical current of the light-receiving element 7. |
