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  4. No.32 January,2003
Fujikura Technical Review

No.32 January,2003

Broad band service to the home has been started in Japan by the nation-wide deployment of FTTH (Fiber To The Home) technologies. This service will come into wide use by the acceleration of internet access demand year by year. The key technology which support this broadband telecommunication service on the backbone stage is D-WDM (Dense Wavelength Division Multiplexing) transmission system. Polarization maintaining components such as Pola-muxTM (Polarization beam combiner), PM-FBG (Fiber Bragg Grating) are indispensable devices to create ultimate high capacity D-WDM system. Our most advanced device, Polarization Maintaining Optical Amplifier is a flagship products for the Ultra Dense WDM system which is upcoming new generation technology. Fujikura's optical devices for this D-WDM application always have world leading performance and reliability to create next generation telecommunication age.


Polarization Maintaining Optical Components with Fused-taper Structure

Polarization-maintaining (PM) optical components are quite important for the DWDM transmission technology of the next generation, such as a polarization-interleave multiplexing technology. In this paper, we introduce novel PM couplers: Polarization Beam Combiner (PBC), Polarization Maintaining Tap (PM-Tap) coupler, and Polarization Maintaining WDM (PM-WDM) coupler, with fused-taper structure. These PM-couplers are suitable for polarization-maintaining EDFA due to excellent optical properties and high reliability.

High Performance Dispersion and Dispersion Slope Compensating Fiber Modules for Non-zero Dispersion Shifted Fibers

Slope compensating and dispersion compensating fibers (SC-DCF) for a low dispersion slope non-zero dispersion shifted fiber (NZ-DSF) and a large effective area NZ-DSF were designed and fabricated. The SC-DCFs realized dispersion slope compensation ratios of 100 % in the C-band or L-band while the fibers maintained dispersion and bend loss similar to those of SC-DCFs for standard single-mode fibers (S-SMF). In addition to the dispersion characteristics, thermal coefficients of dispersion for the fibers were measured. It has been confirmed that the coefficient is proportional to dispersion slope even for the fibers with large negative dispersion slopes. Nonlinearities of the SC-DCFs were evaluated. It was confirmed that nonlinear phase shifts and stimulated Brillouin scattering thresholds of the fibers were similar to those of SC-DCFs for S-SMF. The fibers were packaged into modules, and loss spectra, temperature characteristics and reliabilities on the modules were evaluated. As a result, it has been confirmed that the modules have good optical performance and high reliability.

SFF and SFP Optical Transceivers

We have developed small high-speed optical transceivers called SFF (Small Form Factor) and SFP (Small Form-factor Pluggable) optical transceiver suitable for use in Gigabit Ethernet, Fibre Channel and Synchronous Digital Hierarchy (SDH) applications. It has excellent transmit / receive performance that meets standards such as IEEE802.3z, ANSI FC-PI and ITU-T G.957.

24-Fiber Ribbon Fusion Splicer

A small mass fusion splicer for splicing up to 24-fiber ribbon has been developed. This splicer (FSM-40R24) is the first splicer developed and available in the world for splicing 24-fiber ribbon. Naturally, the system will provide very great productivity benefits due to the 24-fiber ribbon splicing capability. Moreover, it is very significant that is applicable to not only 24-fiber ribbons, but to high performance splicing of all other ribbon fiber counts up to 24-fiber, as well as single fiber splicing. Furthermore, these capabilities have been achieved with a splicer that is designed to have great utility in harsh field conditions, including aerial or underground environments.

Snow-melting Magnetic Material Wire

Snow accumulation on transmission line conductors may cause various problems such as galloping oscillation. As such, snow accumulation on transmission lines is one of the crucial problems. A method using the heat generated by the alternating magnetic field of a magnetic material wire has been developed and put into practical use. However, the method using conventional magnetic material can not gain sufficient calorific value to melt snow at some transmission lines which only low current pass in winter season. To solve these problems, we attempted to optimize alloy composition of Fe-Ni. In this research, we manufactured snow-melting wires varying Ni content and evaluated these magnetic characteristics and calorific value. In this result, magnetic characteristics and calorific value improved with increasing Ni content. A magnetic material optimized alloy composition showed calorific value of approximately 1.4 times as much as conventional magnetic material.

Construction of the World's First Long-Distance 500kV XLPE Cable Line

Underground transmission line applying two circuits of 500kV 2,500mm2 aluminum sheathed XLPE cable, named "Shin-Toyosu Line" has been constructed with Tokyo Electric Power Company. This is the world's first long-distance 500kV XLPE cable line with straight through joint and designed to supply power to Tokyo Met. Completed route consists of two circuits and route length is approx. 40km, Fujikura has supplied the cable with one circuit of 20km, 51 phases of joint and 3 phases of SF6 sealing end. The supplied cable length was approx. 1,800m in the maximum, it made the number of joints reduced and compressed the construction schedule. This paper presents an overview of the project.

Membrane Switch Module

We have been producing membrane switches with mounted electronic chip parts and those that are connected with liquid crystal displays or transparent touch panels. Recently, it is required to attach membrane switches with various kinds of mechanical parts such as switches, potentiometers, panels and cabinets. These combined modules enable our customers to reduce the assembly labor, and they add new value and new function to our products. Furthermore, the size and the cost of final equipments can be reduced, since we can optimize the design of the modules from the viewpoint of wiring board level. For adopting these demands, we have developed various constituent technologies, and we have started manufacturing membrane switch modules.

High Speed Cable

The latest high speed transmission cables for the interfaces of personal computers, servers, and other information terminals are available in many types. The cable and connector specifications depend on the specifications for the physical layer of the applicable interface standards. Presented herein are the places of use and features of some of the most representative types of high speed transmission cables currently in use.

High Aspect Ratio Through-hole Interconnections in Silicon Substrates

We have developed key technologies to form conductive interconnections through a thick silicon substrate, which are potentially applied for 3D stacking of semiconductor devices or packaging of Micro Optical Electro-Mechanical System devices. In this paper, we demonstrate to form metal filled through-holes in thick Silicon substrates (t = ~500 micro m) mainly using Photo Assisted Electro-Chemical Etching and Molten Metal Suctioned Method. The through-holes had 15 micro m in the diameter and the aspect ratio of 35. And the maximum density was 500 THs/cm2. The dielectric breakdown voltage of the through-holes was more than 500V. In result of a radioisotope leak test using Kr-85, the leakage rate of through-holes between the front and the back of the substrate was lower than the limit of detection (1 * 10-15 Pa . m3/sec.).

Touch Mode Capacitive Pressure Sensor

Touch Mode Capacitive Pressure Sensor proposed by Ko, et al. has great potentialities for several applications, because of its high sensitivity, good linearity and low temperature dependence of electrical performances. We have been developed the Touch Mode Capacitive Pressure Sensor for a tire pressure monitoring system, which can be implanted in tire rubber through its curing process. The sensor needs high burst pressure greater than 3.5MPa, which is the maximum pressure during the process. The purpose of this work is to find the cause of diaphragm breakage in lower applied pressure, and to obtain the sensors that have the required minimum burst pressure for the tire pressure monitoring system. We especially focused on surface morphology of diaphragm and found that etch-pits on the diaphragm made the strength weak. The etch-pits were generated during etching process to form the diaphragm. Finally, we could improve the etching process and develop the Touch Mode Capacitive Pressure Sensor, which had a high burst pressure enough to be applied in the tire pressure monitoring system.