| 摘要 |
PURPOSE: To obtain a stabilized frequency shifter having no temperature dependency, and a highly accurate and reliable optical displacement measuring apparatus, in which a voltage amplitude corresponding to optical phase shift of 2πcan be sustained constantly regardless of temperature variation. CONSTITUTION: The frequency shifter comprises an electrooptic element 10 having refractive index variable with the voltage, and a power supply means for applying a sawtooth voltage to the electrooptic element 10 through electrodes 11a, 11b formed thereon. In the frequency shifter 101 where a luminous flux 3 passing through the electrooptic element 10 is frequency modulated by a sawtooth voltage being applied from the power supply means, a predetermined temperature dependency is imparted to the sawtooth voltage. |
