Site: Hitachi Cable, Ltd.
Takasago Branch, Hitaka Works
880 Isagozawa-cho
Hitachi-shi, Ibaraki-ken
319-14 Japan
Tel.: 0294 42 9911
Date Visited: November 15, 1994

Report Author: D. Crawford



D. Crawford
S. Forrest
B. Hickernell
F. Leonberger
C. Uyehara


M. Onishi
Deputy General Manager, Hitaka Works
Dr. H. Kajioka
Manager, Optical Fiber Gyro Section
Dr. T. Yuhara
Research Engineer, Optical Fiber Gyro Section
Dr. H. Ohuchi
Gen. Manager, First Dept., Optoelectronic Systems Lab
S. Yamamoto
Senior Researcher, Third Dept., Optoelectronic Systems Laboratory


Hitachi Wire Plants was established in 1918 as a wire and cable production company. In 1956, Hitachi Wire and Cable became independent of Hitachi, Ltd., and in 1966 it was renamed Hitachi Cable, Ltd. Today, the company employs 6,800 staff members. Of plant personnel, 1,063 are engineers, 462 are technicians, and 3,219 are workers. The research laboratory employs 388 personnel, with other employees distributed throughout the plants, research lab, head office, and branch offices. The company's six plants are described in Table Hitachi.1.

Hitachi Wire and Cable has capital stock of $258 million, with net sales of $2.85 billion in 1993, of which 3-4% is invested in the company's research and development activities. The Hitaka plants (including Takasago) accounted for 59% of company sales in 1993. Table Hitachi.1 Hitachi Cable's Plants in Japan

Hitachi Cable has overseas subsidiaries and affiliates in the United States, Singapore, Malaysia, Thailand, and Hong Kong.

Six percent of the company's business is in electronics (fine wire and IC lead frame), and 6% is in communications cable, of which submarine fiber-optic cable is one product. Overall, fiber-optic cable accounts for one-third of the communications cable business. Note that one of the largest segments of its business (15%) is optoelectronic products and cable accessories. Further breakdown of this category was not available in the literature and information provided.

In R&D, the company employed 435 persons as of March 1994: 30% in the optoelectronic systems laboratory, 15% in the systems materials laboratory, 11% in the advanced research center, 13% in R&D in the factory, and 31% in the power systems laboratory. According to R&D fields, 40% of these employees are directly associated with optoelectronics and communications technology, and 11% are associated with electronic components technology.


The JTEC panel visited two nearby Hitachi plants, Hitaka Works and Takasago Works, each of which has some optoelectronics activity. In the area of optoelectronics technology, two main areas of activity were discussed:

Sensing and Surveillance Systems

These systems are designed for measurement and control of motion and improved reliability for electrical power transmission systems. Applications include fiber-optic gyros for motion measurement; pipe-mapping and gyro compasses; FTR for salt deposition on insulator monitoring systems; and gas analysis monitoring for degradation of oil-filled cable.


Work on optical subscriber systems for communications includes planar waveguide devices on silica for star coupler, optoelectronic bidirectional modules, and high delta n waveguides.

Hitachi Cable is the largest producer of cost-effective, high-performance FOGs for both industrial and commercial applications. Hitachi began development of polarization-maintaining fiber in 1978 and began FOG development in earnest in the mid-1980s. From 1981-1990, polarization-maintaining fiber devices were developed, and from 1986 on the necessary signal processing capability was developed. The FOG project transferred from the research and development center to the Takasago Works in 1988 with 9 personnel. The project now employs 70 personnel and has a large production base, with standardization of the product in automotive navigation applications. This product is used in the Toyota Mark II, was chosen by R&D magazine as one of the most promising new products of 1993, and thousands of units have been delivered since 1992. (See Fig. 6.6) It is the automobile application that is the market driver for other applications. The automotive application is very cost-sensitive; the company has made a major investment in the manufacturing technology and has employed considerable R&D resources in cost-reduction techniques. The panelists walked through the manufacturing facility for FOG products, part of which was automated. This is the largest manufacturing line in the world for FOG products, with a capacity of 2,500 units/month/shift (two 12-hour shifts in one day). This production line was established in 1992.

Other applications for FOG sensors include an FOG mapping system used to calculate the position of pipes, and an FOG used to establish North (a gyro compass).

A major effort to reduce cost in these fiber-optic devices includes development of LiNbO3 integrated optic circuits that perform polarizer, coupler, and phase modulator functions, and that can be produced at low cost and high volume using microelectronic-compatible technology.

For communications applications, Hitachi Cable is developing activities in high-silica guided wave products; so-called planar lightwave circuit products; 2 x 2, 1 x 8, and 2 x 16 star couplers with fiber pigtails; hybrid integrated modules incorporating lasers and photodetectors; and custom device development according to customer needs. There are currently 40 people working in the area of planar optical guided wave devices, 30 in research and development, and 10 in products. It appears there is not yet an established market for the product, although the company foresees a large market in FTTH, FTTO, and so forth. At least half of the personnel working in this activity are looking at packaging issues.

The primary emphasis is on high silica waveguides on silica substrates. These devices offer high performance and potential for fairly simple optical integration. The second approach under consideration is high silica waveguides on silicon substrates, the attraction being in the possibility for OEIC and hybrid integration. The groups have also considered LiNbO3 III-V semiconductor and polymer activities, but these are currently not judged to be as competitive for the totally passive applications discussed. The current waveguide silica-on-silica technology is perceived to offer high reliability, superior optical performance (low insertion loss, low polarization dependence loss, and compatibility with optical fiber), and future expandability in integrated circuits and low-cost.

Note that these products offer the potential to fusion-splice the waveguides and optical fibers. This is a considerable merit. Hitachi Cable claims to be able to fusion-splice these fibers to chips with +/- 0.5 microns in the horizontal and vertical directions.

The JTEC team also toured the production facility for this technology. The available cleanroom area is very large, although the equipment seemed somewhat limited. Hitachi Cable representatives are optimistic about these products, which are at a less advanced product realization stage than the FOG discussed above.


The JTEC team's hosts discussed the method used to select research projects. Each manager has the opportunity to present his technology to the President once or twice each year, when the President selects projects for investment. They did indicate, however, that many underground projects do exist and are maintained discreetly by managers until promising results are obtained.

Hitachi Cable representatives also indicated that engineers and scientists occasionally do consult with the Hitachi marketing department at project conception.

On the manufacturing line, the employees are mainly high school graduates who receive on-the-job training. In the FOG and waveguide technology areas, the division between R&D and manufacturing is somewhat amorphous. The selection of employees who might become what in the United States would be part-time graduate students is primarily market-driven (what type of expert the company foresees it may need helps determine the appropriate employee), although no specific model is followed.

Published: February 1996; WTEC Hyper-Librarian