| 摘要 |
PROBLEM TO BE SOLVED: To provide a high frequency oscillator executing PLL control normally even for thermal contraction of an optical fiber due to an ambient environmental temperature. SOLUTION: The high frequency oscillator modulates a laser beam generated by a laser light source by an optical modulator, converts the modulated laser beam transmitted through an optical fiber to a high frequency signal by a photoelectric converter, takes out a predetermined passband component from the converted high frequency signal by a bandpass filter, feeds back the frequency of the high frequency signal of the predetermined passband component to the optical modulator as a modulation signal, and outputs it as an oscillation signal. The high frequency oscillator is provided with: a PLL control means for performing control such that the frequency; and phase regulation means for adjusting the phase of the high frequency signal such that a change in an oscillation frequency of the high frequency oscillator is kept within a predetermined frequency pull-in range of the PLL control means. COPYRIGHT: (C)2010,JPO&INPIT
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