| 摘要 |
PROBLEM TO BE SOLVED: To apply an optical loop back device to optical ping-pong transmission by reflecting light, which is emitted from each lens, toward the lens at the time of approach to an optical path between the lenses. SOLUTION: When a light reflector 15 is moved to the position of a real line and light is transmitted from a transmitter/receiver 1 in the case of executing optical loop back, this light is passed through an optical fiber 5 and made incident to a lens 9. Then, it is turned to parallel light and emitted by the operation of the lens 9 and the light reflector 15 is irradiated with the light. This light is completely reflected on the light reflector 15, made incident to the lens 9 again and returned through the optical fiber 5 to the transmitter/ receiver 1. At such a time, the return of light is detected by the transmitter/ receiver 1 so that a fault such as the disconnection of the optical fiber 5 can be discovered. In this case, when the light reflector 15 is provided so as to move forward and backward, the optical loop back can be performed to bidirectional communication to use one optical fiber 5 and this device can be applied to an existing optical fiber communication path as well. |
