Pioneer Electronic Corporation

Tohoku Pioneer Electronic Corporation

Tohoko Pioneer Electronic Corporation

Tetsuro Endo

Kiichiro Shinokura

Kichiro Shinokura

An optical coupling device for coupling a semiconductor laser emitting a diverging laser light to a converging optical system converging the laser light onto a rectangle end surface of an optical wavelength converter, comprises: a rotator for rotating the semiconductor laser about an optical axis thereof; a collimator disposed in the optical axis for converting the diverging laser light to a parallel beam along the optical axis; and a polarization rotator for rotating a plane of the electric field vibration of the parallel beam about the an optical axis to guide the beam to the converging optical system, thereby controlling the plane of the electric field vibration direction of the fundamental wave to couple the fundamental wave to a rectangle end surface at a high efficiency.

Optical coupling with electric field rotation

An optical wavelength converter includes an optical wavelength converting element having a multimode waveguide of a core of a nonlinear optical material with a high temperature dependency or temperature coefficient of an index difference for the fundamental wave and secondary harmonic and a clad surrounding the multimode waveguide for converting a wavelength of a fundamental wave entering the multimode waveguide to a 1/2 wavelength of a secondary harmonic; and a temperature tuning device for changing a temperature of the clad and the multimode waveguide within a predetermined temperature range to maintain a phase matching temperature of the fundamental wave and the secondary harmonic in the optical wavelength converting element. The temperature tuner changes the temperature coefficient so as to select a pertinent pair of the fundamental wave and secondary harmonic modes for a wavelength conversion. The multimode waveguide structure has a large sectional area which enables output of a stable high power of secondary harmonic and is easily manufactured.

Optical wavelength converter with temperature tuning

An optical wavelength converting device comprises; a semiconductor laser emitting a fundamental wave; a waveguide-type optical wavelength converting element having a core made of a nonlinear optical material and a clad surrounding the core; and a converging optical system for converging the fundamental wave onto an input end of the waveguide, characterized in that the device further comprises; an adjusting optical system for adjusting a quantity of backward light backed from the optical wavelength converting element to the semiconductor disposed in the coupling optical system; a reflecting portion for reflecting the fundamental wave disposed in the an optical wavelength converting element or the coupling optical system; a current controller for changing an electric current to be supplied to the semiconductor laser; and an optical-path-length stabilizing device comprising a supporting plate for supporting the semiconductor laser, the coupling optical system and the an optical wavelength converting element to keep constant an optical path length between the semiconductor laser and the reflecting portion; and a temperature tuner for changing temperature of at least one of the supporting plate and the semiconductor laser to keep a predetermined temperature thereof constant.

Optical wavelength converting device

An optical waveguide type light wavelength shifter device has a core made of a nonlinear optical crystal and a cladding. The optical waveguide type light wavelength shifter device is provided with a thermoelectric element so that wavelength variation of the second harmonic wave resulting from a variation in the wavelength of an incident light can be minimized.

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Tendo, Japan

Tetsuro Endo