| 摘要 |
PURPOSE:To make a consumption power less, simplify a circuit, and further make a voltage of a power supply lower. CONSTITUTION:This embodiment is constituted as follows: A pulse current source 20 to be switched corresponding to H, L of an input transmission data is in series connected to a laser diode 7 between power supply voltage terminals 30a and 30b. A bias current source 21 is in parallel connected to the pulse current source 20. An APC control unit 22 for generating a control voltage is provided so that a light-emitting power of the laser diode 7 may be held at a constant. A pulse current control unit 19 for controlling a pulse current by applying a control voltage derived from the APC control unit 22 is provided. |
