| 摘要 |
PROBLEM TO BE SOLVED: To provide an optical coupling circuit capable of highly efficiently coupling an optical transmission path with a light-receiving element and being made low in price by filling a material having a refractive index equal or less to that of the optical transmission path between the optical transmission path and the light-receiving element. SOLUTION: On a Si substrate 1, a mirror surface 6 is formed which reflects exit light from an optical fiber 4 and lets a light receiving surface 7 of a photodiode(PD element) 2, and a resin 8 having a refractive index almost equal to that of the optical fiber 4 is filled in the optical path of the PD element 2 and the optical fiber 4. For the resin 8, silicone resin is suitably used, which has a refractive index equal or less to that of the core of the optical fiber 4. The PD element 2 is a front face incident type with 80 μm light-receiving diameter, and the optical fiber 4 is a multi-mode optical fiber having a 62.5 μm core diameter and a 125 μm outer diameter. Further, a space between the PD element 2 and the optical fiber 4 is 155 μm, and the refractive index of the resin 8 is 1.47 equal to that of the optical fiber 4. Moreover, a bump 3 is AuSn solder of a 50 μm height. |
