Anritsu Corporation

Takanori Saitoh

Shigeru Kinugawa

Shigenori Mattori

Yoshifumi Takahashi

Kenichi Nakamura

An FBG sensor system which has a wavelength-tunable light source for emitting light wavelength-swept at a predetermined sweep period, a photodetector for receiving reflected light of measurement light directed to be incident on an optical fiber including an FBC, a processing unit for measuring the wavelength of the reflected light received by the photodetector, and optical pulse generator means that generates a pulse having a predetermined period in synchronism with the sweep period in order that the light from the wavelength-tunable light source is converted into an optical pulse. The sweep period is such that a receipt time of the reflected light in the photodetector is after termination of incidence of the optical pulse on the optical fiber. The predetermined period of the pulse is such that an incidence time for a next optical pulse is after the receipt of the reflected light in the photodetector.

FBG sensor system

An optical spectrum analyzer measures to-be-measured light while carrying out calibration processing for correcting wavelength information of spectrum data of the to-be-measured light by a wavelength information correction device through a storage device based on the spectrum data of reference light that is obtained by causing the reference light whose wavelength is known to be incident on a tunable wavelength filter from light incident devices at all times together with the to-be-measured light. Since the optical spectrum analyzer can continuously measure the to-be-measured light in a wide wavelength range at high speed while maintaining high wavelength accuracy, it can continuously obtain the spectrum data of the to-be-measured light with high wavelength accuracy even if it is installed in a place in which an environment intensely changes.

Optical spectrum analyzer

Faraday rotators each have a Faraday element which rotates light and a magnetic field generator for applying a magnetic field to the Faraday element. A wavelength plate is disposed between the Faraday rotators and it retards the light. A polarizer transmits, of the light, light having a predetermined plane of polarization which has been rotated by the Faraday rotators and retarded by the wavelength plate. An optical receiver receives the light transmitted by the polarizer and outputs a light receiving signal which corresponds to the amount of light received. A signal generator outputs a control signal for polarizing the light to be measured into at least four polarization states to the magnetic field generator. A signal processor determines Stokes parameters which indicate the polarization state of the light to be measured based on the four polarization states, and the light receiving signal corresponding to each of the four polarization states.

Polarization analyzer using a plurality of Faraday rotators

A tunable laser source apparatus includes an external cavity. The external cavity includes a semiconductor laser and a diffraction section. At least one laser output end facet of the semiconductor laser is covered with an AR coating. The diffraction section includes a first reflector and a diffraction grating, and has wavelength selectivity with which light emerging from the end facet of the semiconductor laser which is covered with the AR coating is received, and light having a predetermined wavelength is selected and reflected toward the semiconductor laser. The semiconductor laser further includes an angle detection section and a control section. The angle detection section detects the angle defined by the optical path of the light emerging from the semiconductor laser and the optical path of the diffracted light reflected by the diffraction section. The control section controls at least the cavity length of the external cavity or the selected wavelength of the diffraction section to set the angle detected by the angle detection section to zero.

Growing community of inventors

Zama, Japan

Takanori Saitoh