| 摘要 |
Disclosed is an optical heterodyne frequency modulator for outputting an FM signal by driving a frequency modulating laser diode with an input signal to generate an FM optical signal, combining waves of a local optical signal with waves of the FM optical signal, and subjecting the combined signal to optical heterodyne detection to output the FM signal which is frequency-modulated by the input signal. A signal having a phase opposite that of a signal input to a frequency modulating laser diode is generated, the amplitude of the FM optical signal, which is output by the frequency modulating laser diode, is controlled in such a manner that the optical power is rendered constant, the amplitude-modulated FM optical signal and the local optical signal are combined, and the combined signal is then subjected to optical heterodyne detection, whereby an FM signal is produced as an output.
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