Optical measurement device

An optical measurement device comprising:

• a first light source configured to generate measurement light including a first wavelength;
• a second light source configured to generate stimulation light including a second wavelength shorter than the first wavelength;
• an optical coupler, the optical coupler being a WDM optical coupler, the WDM optical coupler including an optical fiber provided to be branched between an output end and first and second input ends, the first input end being optically coupled to an output of the first light source, the second input end being optically coupled to an output of the second light source, and the WDM optical coupler combining the measurement light with the stimulation light to generate a combination light and outputting the combination light from the output end;
• a photodetector configured to detect an intensity of reflected light or transmitted light from a measurement target object and output a detection signal;
• an optical system configured to guide the combination light toward a measurement point on the measurement target object and guide the reflected light or transmitted light from the measurement point toward the photodetector;
• and
• a scanner configured to move the measurement point,
• wherein the optical fiber has a property of propagating light in a single mode for at least the first wavelength.