| 摘要 |
An optical transmitter including a laser diode (10) and achieving automatic slope variation compensation thereof. A photodetector (12) detects the output optical signal of the laser diode. One control loop (1) maintains the mean optical signal power output constant by adjusting the bias current Ib appropriately. Another control loop (2) adjusts the modulation current Imod to maintain the a.c. optical signal power constant. This is achieved by determining a voltage V2 corresponding to the mean a.c. optical signal power by rectification and comparison with a reference Vref2 to produce an error signal DELTA V2. The a.c. optical signal power is thus used to indicate a reduction in slope efficiency.
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