Optical measurement device and optical measurement method

An optical measurement device comprising:

• a measurement light pulse source configured to output a plurality of measurement light pulses having different temporal waveforms and different center wavelengths;
• a spectroscopic element or a spectroscope configured to spatially separate the plurality of measurement light pulses for each center wavelength and cause the plurality of measurement light pulses to be incident on a measurement object;
• a wave synthesizer unit configured to synthesize the plurality of measurement light pulses reflected by the measurement object or transmitted through the measurement object and emit the plurality of measurement light pulses onto one optical path;
• an optical detection unit configured to receive the plurality of measurement light pulses emitted from the wave synthesizer unit and output a temporal waveform signal of the plurality of measurement light pulses;
• and
• a measurement unit configured to measure timings when the plurality of measurement light pulses each are received by the optical detection unit or a difference between the timings on a basis of the temporal waveform signal,
• wherein the measurement light pulse source includes:
• a first pulsed laser light source configured to output a wideband light pulse having a plurality of wavelength components;
• and
• a pulse forming unit configured to form the plurality of measurement light pulses from the wideband light pulse,
• wherein the pulse forming unit includes:
• a first array waveguide diffraction grating configured to spatially separate a plurality of wavelength components included in the wideband light pulse for each wavelength;
• a plurality of optical fibers each configured to transmit the plurality of wavelength components spatially separated for each wavelength;
• and
• a second array waveguide diffraction grating configured to synthesize the plurality of wavelength components transmitted by the plurality of optical fibers and output the plurality of wavelength components as the plurality of measurement light pulses, and
• wherein the plurality of optical fibers differ from each other in a refractive index.

An optical measurement method comprising steps of:

• outputting a plurality of measurement light pulses having different temporal waveforms and different center wavelengths;
• spatially separating the plurality of measurement light pulses for each center wavelength and causing the plurality of measurement light pulses to be incident on a measurement object;
• synthesizing the plurality of measurement light pulses reflected by the measurement object or transmitted through the measurement object and emitting the plurality of measurement light pulses onto one optical path;
• receiving the plurality of measurement light pulses emitted onto one optical path, and outputting a temporal waveform signal of the plurality of measurement light pulses;
• and
• measuring timings when the plurality of measurement light pulses each are received or a difference between the timings on a basis of the temporal waveform signal,
• wherein the outputting includes:
• outputting a wideband light pulse having a plurality of wavelength components;
• and
• forming the plurality of measurement light pulses from the wideband light pulse, and
• wherein the forming includes:
• spatially separating the plurality of wavelength components included in the wideband light pulse for each wavelength;
• modulating at least one of a phase and an intensity of each of the plurality of wavelength components spatially separated for each wavelength so that a plurality of light pulses having different temporal waveforms and center wavelengths are formed when the plurality of wavelength components are synthesized;
• and
• synthesizing the plurality of wavelength components, the at least one of the phase and the intensity of the wavelength components having been modulated, and outputting the plurality of wavelength components as the plurality of measurement light pulses.

An optical measurement method comprising steps of:

• outputting a plurality of measurement light pulses having different temporal waveforms and different center wavelengths;
• spatially separating the plurality of measurement light pulses for each center wavelength and causing the plurality of measurement light pulses to be incident on a measurement object;
• synthesizing the plurality of measurement light pulses reflected by the measurement object or transmitted through the measurement object and emitting the plurality of measurement light pulses onto one optical path;
• receiving the plurality of measurement light pulses emitted onto one optical path, and outputting a temporal waveform signal of the plurality of measurement light pulses;
• and
• measuring timings when the plurality of measurement light pulses each are received or a difference between the timings on a basis of the temporal waveform signal,
• wherein the outputting includes:
• outputting a wideband light pulse having a plurality of wavelength components;
• and
• forming the plurality of measurement light pulses from the wideband light pulse,
• wherein the forming includes:
• spatially separating a plurality of wavelength components included in the wideband light pulse for each wavelength;
• transmitting the plurality of wavelength components spatially separated for each wavelength using a plurality of optical fibers;
• and
• synthesizing the plurality of wavelength components transmitted by the plurality of optical fibers and outputting the plurality of wavelength components as the plurality of measurement light pulses, and
• wherein the plurality of optical fibers differ from each other in a refractive index.