| 摘要 |
PURPOSE:To simplify the reception circuit and to improve the frequency characteristics, by inserting an optical beam splitter between an optical fiber and a condencer lens. CONSTITUTION:A light propagated in a core 11 of an optical fiber 1 is spread with a prescribed angle and irradiated as an optical output 2 including a lower order mode 21 and a higher order mode 22. The output 2 is transmitted to a photodetector 5 via an optical beam splitter 3 having a pin hole 31 and applied with coating preventing the reflection of the higher order code 22, and a condencer lens 4. Further, the distance D between the splitter 3 and the fiber 1 is changed, allowing to prevent the waveform change in the optical output 2. |
