| 摘要 |
PURPOSE:To realize the bidirectional optical fiber transmission system low in cost, and simple and practical, by switching control of light emission and photo detection in time sharing, by using the light emitting element as photodetector with the selector switch. CONSTITUTION:The electric signal entered to the bidirectional transmission system 39 drives the light emitting element 12a via the light emitting element drive circuit 13a, and change-over switch 19a to transmit optical signal to the optical fiber 31, and this optical signal is incident to the photodetector 12b at the reception end. The output current of the element 12b passes through the photo current amplifier circuit 14b via the change-over switch 19b and goes to the output terminal 16b. The electric signal input from the opposite terminal 15b reaches the terminal 16a with the element 12b playing light emission function and with the element 12a playing photo detection function. In this case, the switch control circuits 18a, 18b control the switches 19a, 19b and the switches 20a, 20b in time sharing, and control is made so that the switches 20a, 20b are OFF when the switches 19a, 19b are ON. Thus, practical bidirectional optical fiber transmission system can be realized. |
