| 摘要 |
An optical communication system includes a directly modulated semiconductor laser (10), the output of which results in pulse shortening of light pulses corresponding to high level bits of a high frequency electrical digital modulating signal. A travelling wave laser amplifier (14) coupled to the laser provides an amplified modulated light signal to an optical channel (16), and an optical detector (18) converts a light signal received from the optical channel into an electrical signal. The amplifier has an overshoot characteristic which provides an extended output when overdriven by a high level optical input pulse, and the modulated laser is arranged to provide such high level pulses. The overshoot characteristic of the amplifier thus compensates for pulse shortening produced by the modulated laser in the case of isolated high level bits and the initial bit of a stream of high level bits. The invention also relates to a transmitter and to a repeater for use in such an optical communication system.
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