Matsushita Electric Industrial Co., Ltd.

Tetsuo Taniuchi

Kazuhisa Yamamoto

Kiminori Mizuuchi

Yoichi Sasai

Yoshinobu Tsujimoto

Shigeru Ohmori

Kunihiko Takeshige

A wavelength conversion device exhibiting an excellent wavelength conversion efficiency is provided by forming it in such a manner that an LiTaO.sub.3 substrate is subjected to a proton exchange treatment to form a proton-exchange layer before the proton-exchange layer is subjected to heat treatment to form a domain-inverted structure. Heat treatment is performed at a high temperature rising speed to prevent the thermal diffusion of the proton-exchange layer so that the expansion of the domain-inverted structure to be formed in the proton-exchange layer is restrained. As a result, a higher harmonic wave wavelength conversion device can be provided.

Wavelength conversion device

A frequency doubler of the invention employs a nonlinear optical effect of stabilizing the harmonic output from the frequency doubler. The frequency doubler has an LiNbO.sub.3 substrate, domain inverted regions and a waveguide, which are formed on the substrate, and a thin-film heater formed on the waveguide by depositing Ni-Cr. The temperature of the frequency doubler is controlled by applying a current to the thin-film heater so as to heat the frequency doubler. Even if the wavelength of a semiconductor laser is changed due to change in the environmental temperature, the frequency doubler can stably be operated by changing the temperature of the frequency doubler.

Frequency doubler and visible laser source having a heater

Method of manufacturing wavelength conversion device

A method to fabricate nonlinear optical frequency doubler devices comprised of a process to form periodic tantalum masks on a LiNb.sub.x Ta.sub.1-x O.sub.3 (wherein 0.ltoreq.x.ltoreq.1) crystal substrate, a process to form periodic proton exchanged regions by applying a phosphoric acid treatment, and a process to form an optical waveguide on the surface of said crystal. According to this fabrication method of the present invention, deeper domain-inverted regions can be formed on said crystal surface, and by this, a fundamental wave can be transformed into a harmonic wave at a high efficiency.

Method to fabricate frequency doubler devices

A tapered light wave guide reduced in propagation loss, improved in coupling efficiency and free from the problem of optical damage. An input section, a widthwise tapered coupling section having a depth d2, and a wave guide having a depth d1 are formed on an LiNbO.sub.3 substrate. A depthwise tapered section in which the depth is changed from d2 to d1 is provided to connect the widthwise tapered coupling section having constant depth d2 and the wave guide, whereby a reduction in light propagation efficiency due to optical damage is prevented.

Tapered light wave guide and wavelength converting element using the same

When fabricating an optical wavelength by proton exchange method on a substrate of LiNb.sub.x Ta.sub.1-x O.sub.3 (0.ltoreq.x.ltoreq.1), by using Ta.sub.2 O.sub.5 as the protective mask, the edge of the mask becomes smooth and diffusion of impurity from the protective mask into the substrate does not occur during heat treatment, and the propagation loss may be notably reduced. As a result, the efficiency of the frequency doubler may be enhanced.

Manufacturing method of frequency doubler

A visible laser source comprises a sub mount. A semiconductor laser located on the sub mount has an active layer formed at a surface of the semiconductor laser. The active-layer formed surface of the semiconductor laser opposes the sub mount. An optical nonlinear device located on the sub mount has a waveguide formed at a surface of the optical nonlinear device. The waveguide formed surface of the optical nonlinear device opposes the sub mount. The semiconductor laser and the waveguide are directly coupled to each other for direct application of a fundamental wave from the semiconductor laser to the optical nonlinear device.

Frequency doubled laser apparatus

An optical harmonic generating device having a proton-exchanged optical waveguide possessing an upward convex shape and a structure capable of propagating in a single mode, an input part for receiving an optical wave having a fundamental frequency and an output part for outputting a harmonic wave, disposed on a substrate of LiNb.sub.x Ta.sub.1-x O.sub.3 (O.ltoreq.x.ltoreq.1). The device is an optical harmonic wave generating device with excellent confinement of light, optimum structure and high efficiency.

Optical harmonic generation device

Temperature detector

A fiber optic magnetic field sensor employing Faraday effect. The sensor has two pieces of birefringent substance interposed between the ends of optical fibers and a rod lens for effecting polarization separation. In addition, the sensor employs a reflex optical system in which light reciprocates through a Faraday material. Thereby, a magnetic field sensor has been realized which is more compact and lightweight and lower in cost as well as more accurate.

Growing community of inventors

Kobe, Japan

Tetsuo Taniuchi