Anritsu Corporation

Yoji Sonobe

Takao Tanimoto

A spectroscope device of the dispersion type receives light to be measured and emits it as dispersed light which corresponds to each of wavelengths to be measured. An optical-path switching device directs the dispersed light emitted from the spectroscope device to pass through first and second paths. A first photoelectric converter receives the light which is directed to pass through the first path by the optical-path switching device. A polarizing/separating device polarizes and separates the light, which is directed to pass through the second path by the optical-path switching device, into two polarized lights. Second and third photoelectric converters respectively receive the two polarized lights divided by the polarizing/separating device. An arithmetical process section corrects a first optical spectrum strength according to an output from the first photoelectric converter with at least a ratio of second and third optical spectrum strengths which correspond to outputs from the second and third photoelectric converter to calculate absolute spectrum values of the measured light at every wavelength of the light to be measured.

Optical spectrum analyzer with high performance measurement function

A dispersion-type spectral element designed for reflecting an incident sample light is rotated by a drive mechaism. The sample light reflected by the element is applied to a sample-light receiving device. The device converts the light into a first signal representing the intensity of the sample light. Reference light consisting of beams having various wavelengths over a broad range is supplied from a reference light source to the spectral element. Further, standard light consisting of one beam of a known wavelength is also supplied from a standard light source to the spectral element. The reference light reflected by the element is applied to a reference-light receiving device. The reference-light receiving device converts the reference light into a second signal representing the intensity of the light. An etalon is located in the optical path between the spectral element and the reference-light receiving device. The standard light reflected by the element is applied to the standard-light receiving device. The standard-light receiving device converts the standard light into a third signal representing the intensity of the standard light. An arithmetic unit receives the first, second, and third signals separately, and obtains from the second and third signals a wavelength scale used for calculating from the first signal the wavelength of the sample light.

Spectrometer

A measurement beam emitted from a laser diode is split into two beams by a beam splitter, and one of the two beams is guided to a first port of an acoustic optical element. When a high-frequency signal is applied from a diffraction controller to a piezoelectric transducer, the split beam input into the acoustic optical element from the first port is diffracted and frequency-shifted and output from a second port. If the high-frequency signal is not applied, the input beam rectilinearly propagates without diffracting and is output from a third port. This output beam is guided to a fourth port through an optical fiber. The beam input from the fourth port rectilinearly propagates and is output from the second port. The beam output from the second port is mixed with the other measurement beams split by the beam splitter to be converted to an electrical signal. The electrical signal is analyzed by a spectrum analyzer. When the high-frequency signal is applied to the piezoelectric transducer, measurement using optical heterodyne spectroscopy is performed, and when the high-frequency signal is not applied, measurement using optical homodyne spectroscopy is performed.

Growing community of inventors

Machida, Japan

Yoji Sonobe