Distance measurement device

Abstract

A device includes a signal generation unit that generates a first signal having a first repetition frequency and a second signal having a second repetition frequency higher than the first repetition frequency, a light source unit that generates light whose wavelength is modulated with time through internal modulation based on the first signal, a modulation unit that further modulates, with time, the wavelength of the light using a Doppler effect through external modulation based on the second signal, a splitting unit that divides the light output from the modulation unit into measurement light and reference light, an irradiation unit that irradiates a target object with the measurement light, a detection unit that detects interference light between reflected light from the target object and the reference light, and a calculation unit that calculates a distance to the target object on the basis of an output signal from the detection unit.