Abstract: A wavelength variable light source emits a light whose wavelengths continuously change from a preset start wavelength up to a stop wavelength to a measuring object. A timing information output section generates timing information showing emission timings of lights emitted from the wavelength variable light source and having start and stop wavelengths and a plurality of wavelengths obtained by delimiting the wavelengths between the start and stop wavelengths in predetermined steps. A light receiving section receives the light output from the measuring object and outputs a signal showing a measured value of a received light. A plurality of amplifiers receive the signal output from the light receiving section and amplify the signal at each predetermined amplification factor.

Abstract: A wavelength variable light source emits a light whose wavelengths continuously change from a preset start wavelength up to a stop wavelength to a measuring object. A timing information output section generates timing information showing emission timings of lights emitted from the wavelength variable light source and having start and stop wavelengths and a plurality of wavelengths obtained by delimiting the wavelengths between the start and stop wavelengths in predetermined steps. A light receiving section receives the light output from the measuring object and outputs a signal showing a measured value of a received light. A plurality of amplifiers receive the signal output from the light receiving section and amplify the signal at each predetermined amplification factor.

Abstract: A processing unit reads out, from a memory, wavelength setting data corresponding to wavelength information from a key input section, and outputs a wavelength setting command corresponding to the wavelength setting data to a tunable-wavelength control section and a spectral wavelength control section. The tunable-wavelength control section controls a tunable-wavelength light source section to output a laser beam having a wavelength corresponding to the wavelength setting data. The spectral wavelength control section controls a spectroscope section to perform spectroscopy of the light having the wavelength corresponding to the wavelength setting data and output the resultant light. Output light from the tunable-wavelength light source section whose wavelength has been set is input to an object to be measured. Light passing through the object is input to the spectroscope section. The spectroscope section performs spectroscopy of only the light having the wavelength corresponding to the wavelength setting data.

Abstract: In an external-cavity tunable wavelength light source using a semiconductor laser (LD), an oscillation wavelength is tuned by simultaneously changing a current to be injected to the phase adjustment area of the LD and the rotation angle of a diffraction grating while holding the same external cavity longitudinal mode. A light beam emitted from the AR-coated end face of the LD having the phase adjustment area is collimated by a lens and incident on the diffraction grating. Only a light component having a specific wavelength selected upon spectral dispersion is reflected by the diffraction grating and returns to the LD. With this operation, an external cavity (effective cavity length K) is formed between the LD and the diffraction grating, thereby performing laser oscillation at a wavelength determined by an external cavity longitudinal mode and the cavity loss of the diffraction grating. The effective cavity length K can be changed in accordance with the current to be injected to the phase adjustment area.