| 摘要 |
PURPOSE:To obtain an inexpensive, high-reliability optical transmission module which complies with an increase in function by assembling fiber element wires in one body and thus forming part or the whole of a fiber assembly substrate beyond a range in which there is no evil influence upon output light from a light emitting element and input light to a photodetecting element. CONSTITUTION:An LED20 is connected to the substrate 11 through the part of a wiring conductor 12 and the fiber assembly substrate 11 consists of fiber element wires 13 forming passages for light and a clad part 14 covering them. Then, fibers are a little larger in refractive index than the clad part, the diameter of the fibers is much smaller than the core diameter of transmission line fibers and the light emission and photodetection area of an optical element, and the numerical aperture is equal to or larger than that of the transmission line fibers. Light from the LED has large divergence as shown by 2d in a figure, but the light is entered into the core 16a of a fiber 15 through the core 24 of the fiber assembly substrate. When this fiber assembly substrate 11 is used, this operates as if the light source position viewed from a fiber end surface were closer by the thickness of the substrate. |
