| 摘要 |
An angle modulator branches a light emitted from a light source 101 into a first light and a second light. An optical intensity modulator 104 subjects the first light to predetermined optical intensity modulation with a first electrical signal having a predetermined frequency fc outputted from a first signal source 1031. An optical angle modulator 105 subjects the second light to optical angle modulation with a second electrical signal outputted from a second signal source 1032. An photo-detector 107 homodyne-detects an optical-intensity-modulated signal and an optical-angle-modulated signal that have been coupled by an optical coupler 106 using its square-law detection characteristics, and produces an angle-modulated signal having a center frequency fc as a beat signal. With the structure in which a wide-band angle-modulated signal is generated using the above optical signal processing, it is possible to achieve the angle modulator with suppressed noise independent of phase noise included in the light source.
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