Anritsu Corporation

Shigeru Kinugawa

Shigenori Mattori

Takanori Saitoh

Isao Kobayashi

Hiroshi Furukawa

Koji Kawakita

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 multi-wavelength light source apparatus includes a tunable light source, optical intensity modulator, optical coupler, annular optical delay circuit, and optical gate device. The tunable light source successively changes and outputs a plurality of output lights different in wavelength from one another. The optical intensity modulator outputs a modulated signal light obtained by modulating an amplitude of the output light outputted from the tunable light source over a predetermined time. The optical coupler is optically connected to the optical intensity modulator, and receives the light outputted from the optical intensity modulator. The annular optical delay circuit is optically connected to the optical coupler, and delays a part of the output light outputted from the optical intensity modulator over a time longer than the predetermined time. The optical gate device is optically connected to the optical coupler, receives the output light outputted from the optical intensity modulator and the light passed via the annular optical delay circuit to open a gate at a timing and time width such that all of the signal light modulated over the predetermined time is included one by one for each of the plurality of wavelengths.

Multiwavelength light source device employing annular optical delay circuit

A laser light source apparatus includes a compound cavity and an optical gain medium. The compound cavity includes first, second, and third optical reflection members disposed along the optical axis. The first optical reflection member has a light wavelength selectivity. At least one of the first to third optical reflection members can change its own position on an optical axis in relation to the other reflection members. Two of the first to third optical reflection members are provided opposite to each other with the optical gain medium inserted therebetween, thereby forming a laser light source. The other one optical reflection member is provided so as to form a light path for feeding laser light emitted from the laser light source back to the laser light source.

Tunable wavelength laser light source apparatus using a compound cavity

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

Tokyo, Japan

Shigeru Kinugawa