| 摘要 |
<P>PROBLEM TO BE SOLVED: To solve the problem wherein a suitable pre-modulation level cannot be realized by following the variation in the noise level. <P>SOLUTION: An optical transmission apparatus includes an amplifier for amplifying input radio frequency signal, an oscillator for outputting a pre-modulation signal to be added to the amplified radio-frequency multiplex signal, an adder for adding the output pre-modulation signal from the oscillator to the amplified radio-frequency signal to pre-modulate the added signal, a semiconductor laser driven by the pre-modulated radio-frequency multiplex signal output from the adder, a photoelectric conversion element for photoelectrically converting part of the optical signal output from the semiconductor laser, a detector for detecting the noise level of the optical signal based on the output of the photoelectric conversion element, and an automatic gain controller for regulating the level of the pre-modulated signal output from the oscillator so as to lower the noise level detected by the detector, as much as possible. <P>COPYRIGHT: (C)2004,JPO |
