| 摘要 |
PURPOSE:To output an optical signal having little distortion by adjusting the input signal level of an amplifier operating in the saturation region, adjusting the amount of secondary distortion generated in the amplifier, and mutually cancelling secondary distortion characteristics of the amplifier and that of a semiconductor laser. CONSTITUTION:An amplifier 1 which receives an input signal and outputs a driving signal, a semiconductor laser 2 which receives the driving signal and outputs an optical signal, and an automatic input level adjusting circuit 3 which adjusts the input level of the signal to the amplifier 1 are installed. In the operating characteristics of the amplifier 1, higher order components are contained, which can be changed by adjusting the input signal level. Hence second order component which cancels the second order component in the nonlinear characteristics of the semiconductor laser 2 is generated in the characteristics of the amplifier 1, by suitably setting the input signal level of the amplifier 1 operating in the saturation region, so that an optical signal having little distortion can be outputted. |
