Kabushiki Kaisha Toyota Chuo Kenkyusho

Toyota Jidosha Kabushiki Kaisha

Toyota School Foundation

Hitachi Cable, Inc.

Kazuo Hasegawa

Daisuke Inoue

Tadashi Ichikawa

Hiroshi Ito

Satoru Kato

Kazuya Saito

Tatsuya Yamashita

Tomoya Okazaki

Hiroyuki Matsubara

Akio Sato

Akihito Hongo

Seiji Kojima

Kazumasa Ohsono

Manabu Kagami

Bing Yao

Akari Nakao

Kohei Yanaka

Mitsutoshi Maeda

Arindam Halder

A first fiber is connected to a first end of a third fiber doped with a rare earth element, and a second fiber is connected to a second end of the third fiber. In the third fiber doped with the rare earth element, a central portion of a core is more heavily doped with the rare earth element than a peripheral portion of the core is.

Optical fiber laser device

A laser radar device includes: a light source; a projection light scanner that scans one part of light split off from emission light of the light source, and that generates transmission light for radiating onto a target object; an image forming section that forms plural respective reception lights of the transmission light reflected by respective locations of the target object into an image on a single flat plane as plural image-formation points; an optical receiver that is disposed at the plural image-formation points, and that includes plural unit optical reception sections for mixing each of the plural reception lights together with a reference light and performing optical heterodyne detection; and a reference light scanner that scans or distributes another light split off from the emission light from the light source, and that generates the reference light for radiating onto each of plural of the unit optical reception sections.

Laser radar, and light receiving method of laser radar

A reflector includes a gain fiber and a periodic refraction structure unit. The gain fiber has a core doped with a rare earth element. The periodic refraction structure unit includes a high-refractive-index region that has a predetermined width, that is formed at a predetermined spacing along an optical axis direction of the gain fiber, that is formed across an entire section of the core that is orthogonal to the optical axis of the core, and that has a first refractive index, and a low-refractive-index region that is formed adjacent to the high-refractive-index region, that has a width equal to the predetermined spacing, and that has a second refractive index lower than the first refractive index. A width dof an iperiodic structure of refractive index in the periodic refraction structure unit is given by the equation d=H&#xb7;(&#x3bb;/(2&#xb7;n))+&#x3bb;/(4&#xb7;n).

Reflector, fiber cavity, and fiber laser

A radar apparatus which can simply determine the sign of velocity of an object is provided. Laser light reflected by the object undergoes quadrature optical heterodyne detection performed by mixers, optical detectors, and a &#x3c0;/2 phase shifter, whereby I and Q component signals are output. A frequency analyzer performs FFT on a complex signal composed of the I component signal (real part) and the Q component signal (imaginary part) to thereby obtain its frequency spectrum. Since the frequency spectrum is calculated without being folded back even in a region where the frequency is negative, the sign of the Doppler frequency fd can be determined. When the Doppler frequency fd is positive, the sign of the velocity of the object is a direction toward the radar apparatus. When the Doppler frequency fd is negative, the sign of the velocity of the object is a direction away from the radar apparatus.

Radar apparatus and method of determining sign of velocity

An optical fiber laser, according to the present invention, has an optical fiber including a core to which a rare earth element is added and a clad disposed around the core, and also has an excitation light source for emitting excitation light incident on a side of the optical fiber. The optical fiber has a corrugated shape on the outer circumference of the clad along the longitudinal direction thereof; and the optical fiber is wound in a spiral form and is bundled in such a way that adjacent sides of the clad are brought into contact with one another.

Optical fiber laser and exciting method using same

Each of guided beam incident portions of an optical waveguide device includes a straight incidence area where laser beams enter, a curved area which curves the laser beams entering from the straight incidence area in a predetermined direction, and a widening tapered area which makes the laser beams that have passed through the curved area parallel or substantially parallel to a propagation direction of the laser beams by decreasing propagation angles of the laser beams.

Optical circuit for condensing laser beams, and light source device

An optical branching device includes a main waveguide and a branching waveguide. A portion of the main waveguide is bent and the branching waveguide is placed close to the bent part of the main waveguide. The branching waveguide has a taper structure such that a width of the branching waveguide is gradually decreased in a propagation direction of light. A central axis of the branching waveguide is tilted from a line extended from a straight part of the main waveguide toward the direction X, or the bending direction of the main waveguide. An input end of the branching waveguide has a normal vector tilted from the central axis of the branching waveguide toward the direction Y, an opposite direction of the bending direction of the main waveguide. With above-mentioned structures, light radiated from the bent part of the main waveguide can be launched into the input end of the branching waveguide and transmitted through the branching waveguide efficiently.

Optical branching devices

Growing community of inventors

Nagakute, Japan

Kazuo Hasegawa