| 摘要 |
PURPOSE:To attain ease of optical output by using a combined output between an output of the 1st reference current source and an output of a switching circuit switching a transmission data given from the 2nd reference current source separately as a reference current source. CONSTITUTION:An output of the 2nd reference current source 13 is outputted as a current switched by a switch circuit 14 corresponding to the transmission data and combined with the output of the 1st reference current source 12 additively. Further, a part of the output light of a laser diode 3 is made incident to a photodetector 8 and a current proportional thereto flows the photodetector 8. The difference between the current flowing to the photodetector 8 and the combined current is averaged by a capacitor 9, amplified by a current amplifier 11 and fed to the laser diode 3. Thus, since outputs of the two reference current sources 12, 13 in use are set independently, the optical output is set easily. |
