| 摘要 |
<p>In an optical unit (a), a first polarizer , a first light wave phase modulator (a Pockels device), a second light wave phase modulator , and a second polarizer are arranged in this sequence. A voltage to be measured is applied to the first light wave phase modulator . A control modulation voltage which has a frequency higher than that of the voltage to be measured is applied to the second light wave phase modulator . A signal processing unit (b) consists of: an O/E converter which converts the intensity of light output from the optical unit (a) into an electric signal; a phase shifter which shifts the phase of the control modulation voltage applied to the second light wave phase modulator by pi /2 radians; an adder 16 which adds an output of the O/E converter 17 to that of the phase shifter 15; and a demodulator c which demodulates output of the adder 16. <MATH></p> |
