| 摘要 |
PURPOSE:To simplify an optical system by using one of two light emitting diodes through the operation of a switch as a light receiving element, and supervising part of the light outputted from other light emitting diodes to eliminate the need for an optical component such as a half mirror, thereby reducing the light coupling loss. CONSTITUTION:In throwing switches 4a, 4b to the position of a drive circuit 3, light emitting diodes 1, 2 are driven by a driver circuit 3, and the light outputted from the light emitting diodes 1, 2 is fetched in an optical fiber 6 via a lens 5. In throwing the switches 4a, 4b to the position of a photodetection circuit 7, a reverse bias voltage is fed from the pbotodetection circuit 7 to the light emitting diode 2, which is used as a light receiving element. In such a case, the light outputted from the light emitting diode 1 is led to the optical fiber 6 via the lens 5. Then the scattered light not coupled with the fiber 6 among the output lights of the diode 1 is received by the light emitting didoe 2 and used as a supervisory signal. |
