Mitsubishi Denki Kabushiki Kaisha

Mitsubishi Electric Corporation

Syuhei Yamamoto

Yoshihito Hirano

Takayuki Yanagisawa

Masao Imaki

Shumpei Kameyama

Kiyohide Sakai

Toshiyuki Ando

Yasuharu Koyata

Yasunori Nishimura

Kenji Masuda

Makoto Satou

Youhei Mikami

Yuji Masuyama

Provided is a device capable of oscillating a plurality of oscillation modes within a laser medium for obtaining a fundamental wave output which is easy in output scaling and high in luminance, thereby enabling a second harmonic conversion which is high in efficiency. The device includes: a laser medium () that is planar, has a waveguide structure in a thickness direction of a cross-section that is perpendicular to an optical axis (), and has a cyclic lens effect in a direction perpendicular to the optical axis () and the thickness direction; a clad () that is bonded onto one surface of the laser medium (); and heat sink () that is bonded onto one surface side of the laser medium () through the clad (), and in the device, a laser oscillation includes a laser oscillation that oscillates in a waveguide mode of the laser medium (), and a laser oscillation that oscillates in a plurality of resonator modes that are generated by a cyclic lens effect of the laser medium ().

Mode control waveguide laser device

To obtain a coherent laser radar device that realizes high reliability and the high output of a transmitted light, the device includes a first optical coupler that branches a laser beam from a laser source into two lights, a local light and a transmitted light, an optical modulator that modulates the transmitted light, a space type optical amplifier that amplifies the modulated transmitted light, a transmitting/receiving optical system that applies the amplified transmitted light toward a target and receives a scattered light from the target, a transmitting/receiving light splitting device that splits the transmitted light and the received light, a second optical coupler that mixes the local light and the split received light together, a photodetector that detects heterodyne of a mixed light, a beat signal amplifier that amplifies a detected signal, a signal processing device that processes an amplified signal, and a display device that displays a processed result. The first and second optical couplers and an optical modulator are structured by polarization maintained type optical elements, and an optical path that extends from the laser source to the space type optical amplifier through the first optical coupler, an optical path that extends from the transmitting/receiving light splitting device to the photodetector through the second optical coupler, and an optical path that extends from the first optical coupler to the second optical coupler are connected by polarization maintained type single mode optical fibers.

Coherent laser radar

On a plate of birefringent crystal made of an LiNbOcrystal or an LiTaOcrystal, a conductive substance is adhered to the whole periphery of side surfaces of the plate that intersect an incident surface of a laser beam, thereby to form a wave plate. A polarizer is provided at the latter stage of the wave plate. A wavelength is monitored based on an output from the polarizer. With this arrangement, based on the use of the LiNbOcrystal or the LiTaOcrystal that can be manufactured by a large quantity at low cost, it is possible to obtain polarization characteristics and wavelength discrimination characteristics that are stable against environmental changes such as temperature and external stress, by suppressing the pyroelectric effect and the piezoelectric effect of these materials.

Wave length plate, wavelength filter and wavelength monitor

Growing community of inventors

Tokyo, Japan

Syuhei Yamamoto