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Release: December 1, 1997


NGK INSULATORS, LTD. (President: Masaharu Shibata, Head Office: Nagoya) started mass shipment of integrated optic devices (IO devices) used as a main component of fiber optic gyroscopes (FOGs).

FOGs employing IO devices, which were developed by Hitachi Cable, Ltd., are now used for vehicle navigation systems and stability control systems. In terms of a vehicle navigation system, Xanavi Informatics Co. has introduced Hitachi Cable's FOGs to their system, which has been installed in Nissan vehicles, such as Cedric and Gloria since June, 1997, and subsequently in Cima. Regarding a stability control system, FOGs are loaded on industrial wireless-controlled helicopters manufactured by Yamaha Motor Co., Ltd., which went on sale in October, 1997.

FOGs with IO devices, which are sensors to measure rotation rate by utilizing two light beams propagating in opposite directions in a fiber loop, are able to measure over ten times more accurately than existing vibratory gyroscopes. Vehicle navigation systems applying FOGs can locate a vehicle's accurate position even if the vehicle cannot receive radio waves from the global positioning system (GPS). NGK's IO device can make FOG as small as a cigarette box.

NGK newly established the mass production line for IO devices, which covers the entire process from producing optical waveguide chips to assembling IO devices, in the plant operated by its Electronics Business Group, located in Komaki-city, Aichi, in October, 1996. Its production capacity, 5,000 to 10,000 units per month, is the world's largest for such products. NGK also has reduced the manufacturing cost to less than one tenth of the former manufacturing cost by establishing their unique techniques such as precision machining and automatic fiber alignment.

NGK is targeting annual sales of several billion yen by 2001 in the field of IO devices, and will continuously develop functional components used in the field of optical communication; at the same time, the low cost of NGK's IO devices will enable NGK to be actively involved in OEM production for other manufacturers.


Fiber Optic Gyroscope (FOG)

Gyroscopes are sensors that measure rotation rate of objects. There are several kinds such as mechanical type and piezoelectric type. FOGs measure rotation rate by utilizing two light beams propagating in opposite directions in a fiber loop. NGK's IO devices, which are used for FOGs, integrate optical parts such as couplars, polarizers, and phase modulators on LN (LiNbO3) substrates. IO devices do not require connections between such optical parts with optical fiber; therefore, it is possible to miniaturize and stabilize the devices; at the same time, to improve their durability and reduce their production cost.

Integrated Optical Device (IO device)

IO devices are functional components which integrate optical waveguide and other optical parts on LN (LiNbO3) substrates by using photo lithography technology. IO devices can switch optical signals or convert electric signals to optical signals by changing the design of optical waveguide, electrode and other optical parts on the substrates. IO devices are adapted to not only FOGs, but also some other products in the field of optical communication system, such as analog modulators for optical CATV, digital modulators for data transmission, optical switches, optical voltage sensors, optical current sensors, and wavelength filters.

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