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  4. No.49 December, 2019
Fujikura Technical Review

No.49 December, 2019


Innovative Solution Using SWR/WTC for Data Centers

In data centers, it is necessary to manage enormous data intensively and effectively. Although data centers have limited floor space, ultra-high density wiring and economical wiring are required. In recent years, Spider Web Ribbon (SWR) has been developed and commercialized, and high density optical cables using SWR have been expanded as ultra-high density and high fiber count technology. In this paper, Fujikura aims to provide an innovative data center wiring solution using SWR and Wrapping Tube Cable (WTC) technologies.


Air-blown Fiber Optic Cable with SWR and WTC Technologies

This paper describes a new type of Wrapping Tube Cable™ (WTC™) called Air-blown WTC, which is installed into microduct with blowing technique. Developed cable can be bent in any direction with suitable stiffness in order to improve blowing characteristics. Moreover, the jacket surface has “concavity and convexity” design to reduce the friction coefficient between the jacket and the inner surface of microduct. 200 μm fibers, complying with ITU-T G.657.A1 recommendation are applied to reduce the diameter and cable weight dramatically 1).

In addition, “Spider Web Ribbon™” (SWR™) with 200 μm fibers can be spliced with existing ribbon structures with 250 μm fibers 2) 3).

The mechanical and environmental characteristics of the developed cable were evaluated, and satisfied with criteria of IEC60794-5-10 4).

The paper mainly focuses on the development of Air-blown WTC with 200 μm fibers having applications such as small diameter, light weight, high fiber count, blowing performance, and easy mass fusion splicing.


12 kW Multi-Mode Fiber Lasers

In recent years, the demand for high power fiber lasers for metal processing applications is expanding. A high output power exceeding a kilowatt is required for metal processing. Generally speaking, the higher the output power becomes, the faster processing is possible. Therefore there is a strong demand from laser processing equipment manufacturers to increase the output power of lasers. Our group possesses all the key technologies required for fiber lasers and has developed and sold fiber lasers with a maximum output power of 8 kW. This time, we have newly developed and designed major optical components such as high power pumping light source, optical fiber circuit, and delivery fiber cable, and successfully developed a 12 kW multimode fiber laser using these new technologies.


Delivery Cable for High Power Fiber Laser

Intensity of reflected light is increased in laser processing with high power CW fiber lasers. A delivery cable having high durability to reflected light is required. We have developed a delivery cable that has high durability to reflected light. Also, our LDC has high resistance to external mechanical force.


Aperture Coupled Beamforming Antenna Array Based on Multiple Layered Substrate

An aperture coupled micro strip-patch antenna for V-band is designed in this paper. It consists of two substrates with slot cut ground in between two substrates with patch at the top and feed line at the bottom of other substrate. Power is coupled from feed line through slotted ground to the patch. This antenna gives good matched results for 59GHz to 63GHz  below 

- 10dB and gain of maximum 14-15dBi for single antenna and more than 24dBi for 16 array elements beamforming array. The beam forming of ± 45 ∞ is shown for channel 2 and channel 3 of IEEE 802.11ad.


Artificial Pinning Centers-doped RE-based Coated Conductors

RE-based coated conductors (CCs) have high critical current characteristics in high temperatures/magnetic fields and are expected to be applied to various superconducting systems. It is known that the critical currents in the magnetic fields are improved by introducing some kind of impurities called artificial pinning centers (APCs) into a superconducting layer of the RE-based CC.

We have been developing high-quality APC-doped RE-based CCs using our original manufacture apparatus. In this work, we report on the results of fabrication and evaluation of APC-doped RE-based CCs aiming for mass production.


Evaluation of delamination strength of Yttrium-Based Superconductor

Yttrium(Y)-based coated conductors (CCs) are expected to contribute to miniaturization and higher performance of superconducting applications by applying them to the superconducting coils, because of their high critical current characteristics in magnetic fields and high temperatures over 20 K. In the coil application, however, there is a problem that the mechanical strength in the direction perpendicular to the tape surface of the Y-based CCs (delamination strength) is relatively weak. In this work, we propose a new measurement method of the delamination strength for the Y-based CCs which has been difficult to quantitatively evaluate.


Application of Deep Learning to Manufacturing

Recently, deep learning, one of the AI technologies, has advanced rapidly and is expected to be applied in various industries. Fujikura applied image recognition technology based on deep learning to the visual inspection of semiconductor laser wafers. By constructing our original network structure and preparing high quality dataset for learning, our visual inspection system achieved over 99% pass / fail judgement accuracy. This system has already been introduced into our semiconductor laser manufacturing process and has been stably operated. This technology has also been applied to visual inspection of crimp-type terminals and achieved over 99% judgement accuracy.


Simultaneous analysis of inorganic ions by LC-ICP-MS

Ion chromatograph, which are analyzers of inorganic ions, generally analyze cations and anions using each separation columns and equipment, and if there are components with close retention time, qualitative analysis it become difficult. Therefore, we conducted various investigations with a liquid chromatograph inductively coupled plasma mass spectrometer as one of ion chromatography alternative methods, and we found that simultaneous analysis with excellent selectivity for inorganic cations and anions is possible.


Study on Primary Screening Method of Phthalic Esters for RoHS 2 Directive

In the revised RoHS Directive (RoHS 2) that will become effective on 22nd July 2019, 4 phthalic esters are added as restricted substances, so it is urgent to construct an acceptance inspection system at the manufacturing bases. The pyrolysis/thermal desorption -GC/MS (Py/TD-GC/MS) official method in IEC 62321-8 determined by IEC, is an excellent method of accuracy and traceability, but it is not suitable for acceptance inspection at manufacturing bases because of its high equipment introduction cost and necessary of expertise for device management. Therefore, we investigated thin layer chromatography (TLC) and direct injection - mass spectrometry (DI-MS) for primary screening. In the study, enough detection sensitivity was gained in both methods. But it was found that some problems in these methods to use at manufacturing bases. To select the screening method, it is necessary to consider cost, accuracy, operability, and so on.