| 摘要 |
PURPOSE:To obtain a bias circuit for an optical receiver with which the optical receiver can be made small. CONSTITUTION:The bias circuit for an optical receiver is applied to an optical receiver employing an avalanche photo diode 5 as a light receiving element and is made up of a high voltage generating circuit 1 and a bias control circuit 3. The high voltage generating circuit 1 applies a predetermined bias voltage to a photo transistor(TR) 311. Furthermore, the bias control circuit 3 comprises a photocoupler 31 and a current control circuit 32. The reverse bias voltage from the high voltage generating circuit 1 is given to an APD 5 via the photo TR 311 of the photocoupler 31. Moreover, a current supplied to a light emitting diode 312 of the photocoupler 31 is controlled by the current control circuit 32. Thus, the bias control circuit 3 adjusts the reverse bias voltage applied to the APD 5. |
