| 摘要 |
PURPOSE:To decrease the accuracy of temperature control to suppress the fluctuation of an intermediate frequency to the minimum by modulating a sine wave in accordance with an input signal, selecting a side wave band obtained by modulation with an injection synchronizing action laser diode and making coincident the intermediate frequency with a sine wave modulating frequency. CONSTITUTION:A light wave from a coherent light source 1 is wave-divided to a first wave and a second wave by a wave-dividing device 3. A modulating circuit 4 amplitude-modulates a sine wave from a crystal oscillator 4c in accordance with the input signal. A light intensity modulator 5 changes the transmitted light intensity of the first wave in accordance with the driving voltage from a modulator 4. An injection synchronizing action laser diode 6 executes the injection synchronizing action to the side wave band of the light wave outputted from the light intensity modulator 5. A wave synthesizing device 8 wave-synthesizes the light wave from a diode 6 and a second wave from the wave synthesizing device 3. The light wave wave-synthesized by a light-receiving element 29 is photoelectric-converted, a frequency mixing is executed and an electric signal, in which an intermediate frequency is omegaC, is outputted. The omegaC is the same as the sine wave modulation frequency of the light intensity modulator 5. The electric signal is amplified by an amplifier 31, demodulation is executed by a detector 32. |
