| 摘要 |
PURPOSE:To measure a mode coupling quantity with a high precision by giving linearly polarized lights from one ends of two principal axes orthogonal to each other and separating to lights spatially and multiplexing them after rotating one of them at right angles and changing relatively the passage length from separation to multiplexing. CONSTITUTION:A linearly polarized light in a specific direction from a light source 1 is taken out through a polarizer 2 and is made incident to one end of a polarization maintaining optical fiber 4 to be measured from an object lens 3, and the exit light from the other end is made incident on a polarizing prism through an object lens 5. One of exit lights branched for individual polarization modes passes a 1/2 wavelength plate 7 and is reflected on a total-reflective mirror 8, and the other passes a half mirror 9 and is reflected on a total-reflective mirror 10, and they are inputted to a photodetector 11 in the same mode through the half mirror 9. The reflective mirror 10 is moved in a certain speed, and a crest value of AC components due to variance of interference intensity of the synthesized light is measured through an amplifier 12 by an AC voltmeter 13. Thus, the mode coupling quantity is measured with a high precision. |
