| 摘要 |
PROBLEM TO BE SOLVED: To provide one nonreciprocal part with plural input/output parts with a low loss and reduce the quantity of leak of light from one port to other ports by providing the input/output part of the isolator with a high-efficiency coupling lens, a light guide element with plural optical circuits, and plural optical fibers in order. SOLUTION: There are four optical fibers 22 at an input part, and they are welded to a light guide element 19 by a carbon dioxide laser. Further, they can be adhered by using an adhesive which serves as a refractive index matching agent. Projection light from the light guide element 19 is made incident on the nonreciprocal part 23 through the light efficiency coupling lens 21. Light passed through the nonreciprocal part 23 is propagated to a light guide element 25 through a high-efficiency coupling lens 24 and then to an optical fiber 27 of an output part. Namely, the light which is propagated through one optical fiber 22 of the input part is projected from one core 26 of the light guide element 19, converged by the high-efficiency coupling lens 24, and made incident on one core 26 of the light guide element 25, so that the light is outputted through one optical fiber 27 of the output part. |
