| 摘要 |
An optical transmitter comprises a laser diode (1) capable of emitting an optical signal in response to an electric current through the laser diode, said current consisting of a bias contribution and a modulation contribution provided by an information signal. The transmitter moreover comprises a photodetector (2) capable of detecting the optical signal and emitting an electrical monitor signal in response to the optical signal. The monitor signal is used for controlling the laser diode by means of first and second control loops. The first control loop controls the size of the bias contribution of the current through the laser diode in response to the monitor signal. The second control loop is adapted to control the size of the modulation contribution of the current through the laser diode in response to the monitor signal; the second control loop comprises a transimpedance amplifier (14) having a low input impedance, said monitor signal being connected to an input on this transimpedance amplifier. The first control loop comprises a current-controlled source (7), and the electrical monitor signal is connected to an input on this current-controlled source. |
