| 摘要 |
PURPOSE:To make a bidirectional module small-sized, lightweight and low-cost, by forming a photodetector section around a small circular light emitting section concentrically and incorporating the photodetector and the light emitting section. CONSTITUTION:The one-cored bidirectional communication system using the same wavelength consists of a one-cored optical fiber connecting two communicating points and a bidirectional module provided at both ends of the fiber. In the bidirectional module, the light emitting section 12 and the photodetector 13 are formed on a light emitting/photo detection base 15 concentrically. The section 12 is formed as a circle sufficiently smaller than the diameter (a) of a core 10a of an optical fiber 10. The section 13 is formed as a ring having an outer diameter (B) almost twice the diameter (a), by leaving a vacant region 14 for insulation around the section 12. The sections 12 and 13 are arranged at a distance D expressed as D=a/2X from the end 17 of the fiber 10, where X is the numerical aperture of the fiber 10. Thus, the input/output of optical signals to the fiber 10 is done with high efficiency and the bidirectional module is incorporated. |
