HOME > BUSINESS > Research and Development > Optical Electric Field Sensor Unit as one of applications of LN waveguides

We are developing RF waves receiving sensor units using laser lights. Optical electric field sensors receive radio waves with laser lights, using optical waveguide modulators utilizing EO effects (Pokels effects) of LiNbO3 crystals. Metal is used only in the film electrodes and small dipole antenna in the sensor head. Even the sensor head and the instrument are connected with optical fibers. Therefore, this sensor will not distort the surrounding electric field and is suitable for precise electric field measurements. Because the sensor head needs no electric power supply, the size of sensor is much smaller than the conventional type sensors. Main applications are measurements of the near field pattern of conventional antenna, and those of the wave distribution inside the automobile body with high degree functions, such as keyless entry system and tire pressure monitoring system. Optical electric field sensors are expected to develop applications in the near future, starting with automobiles. We are also developing Optical Remote Antenna Unit with optical waveguide modulator. Optical Remote Antenna Unit can be constructed using an optical modulator of Mach-Zehnder type without electric power supply, in which the intensity of the light signal transmitted from the receiving to transmitting point facilities varies in response to the intensity of RF signals. The features of this unit are no need of electric power lines at the receiving point ,and long distance transmission of multi-carrier RF waves. Therefore, transmitting and receiving points are easily electrically separated so that this unit can effectively construct the Single Frequency Network (SFN) for Digital terrestrial TV broadcasting. This unit is adopted as one of the separation reception methods in the distribution network of Digital terrestrial TV broadcasting in Japan. Moreover, various applications of this technology are expected in the micro wave photonics field in the near future. 'Optical Remote Antenna' was commercialized through joint development with NHK, NHK ITEC inc. and NEC TOKIN corp. Business of Optical electric sensors and Optical Remote Antenna was transferred from NEC TOKIN corp. to Seikoh-Giken in June of 2006.

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