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Shigeru TOMITA Michito MATSUMOTO Tadashi HAIBARA Tsuyoshi NAKASHIMA Mitsuru KIHARA
We study the most appropriate network architecture for constructing FTTH (Fiber To The Home) networks. We conclude that the Single Star network is the most advantageous for supporting the various services required by subscribers who use broadband signal such as B-ISDN (Broadband-Integrated Services Digital Network). We also study high fiber count cable and low-loss connector which are needed for this network and clarify their requirements. We also show the cable structure, connector structure and connection loss reduction method, which satisfy these requirements. We describe a 4,000-fiber cable with a new structure, a 1,000-fiber one-touch connector, a 40-fiber unit connector and TEC-fiber (Thermally-diffused Expanded Core fiber) which reduces connection loss.
Mitsuru MIYAUCHI Masao TACHIKURA Toshiaki KATAGIRI Makoto SATO Atsushi IDE Tadashi HAIBARA Michito MATSUMOTO
A fully automatic, high-speed splicing machine for optical fiber ribbons has been developed to construct high-count optical cable lines in subscriber loops. Design procedure and detail performance of this machine is discussed in this paper. The developed machine achieves an average splice loss of less than 0.1 dB and a splicing time of about 2 min. for multi-mode five-fiber ribbons.
Mitsuru MIYAUCHI Michito MATSUMOTO Tadashi HAIBARA Noboru KAWASAKI
Mass fusion splice without accurate fiber-core alignment for splicing single-mode fiber ribbon in subscriber optical cable is discussed. Using the surface tension effect in the fusion process positively and suppressing the fiber length variance among fibers in the ribbon, low splice loss of about 0.1 dB was achieved for fibers with small core eccentricity.
Koji SHIBATA Masaaki TAKAYA Kazuo HOGARI Izumi SANKAWA Tadashi HAIBARA
This paper describes a high-speed MT connector assembly method. This technique uses adhesive with a short hardening time, is highly reliable and does not require a polishing process, thus reducing the connector assembly time. First, we investigated an alpha-cyanoacrylate adhesive that hardens quickly and whose adhesive strength does not decrease under high humidity and high temperature conditions, thus ensuring its excellent reliability for outside use. In addition, we investigated variations in the position of the fiber endface on the ferrule endface with a view to obtaining a low insertion loss. Based on the results, we assembled an MT connector using our proposed high-speed assembly method. We confirmed that the assembly time could be reduced to less than 70% of the time required with the conventional method. MT connectors assembled using this technique have a low insertion loss and stable environmental characteristics.
Tadashi HAIBARA Masao TACHIKURA Michito MATSUMOTO Ryosuke ARIOKA
This paper describes a newly developed fully automatic arc-fusion splice machine, by which all splice processes such as stripping, cutting, alignment, fusion, and reinforcement are carried out sequentially without human intervention. Fibers are aligned by using movable arms with 2 µm position accuracy controlled by microscopic image processing. Spliced portion is reinforced by a pair of plates with hot-melt adhesive. By using the new machine, an average splice loss of 0.07 dB and a median tensile strength of 2.6 GPa with reinforcement are obtained for graded-index multimode fibers.
Kunihiro TOGE Kazuo HOGARI Kenji KUROKAWA Nobuyuki YOSHIZAWA Tadashi HAIBARA
This paper describes a low-loss submarine optical fiber cable for a long-distance submarine repeaterless transmission system that employs remote pumping. The features of this system are that it has an increased signal power budget and is cost effective and easy to maintain. First, we investigated the relationship between the signal and pump losses and the Raman gain efficiency of optical fiber needed to achieve a submarine repeaterless transmission system operating at 2.5 Gbps and over a distance exceeding 370 km. We manufactured a submarine optical fiber cable based on the results and confirmed that it had low-loss characteristics. Second, we evaluated the long-term loss stability of the optical fiber with a high-power continuous wave (CW) laser light as the pump source. We confirmed that the loss remained unchanged after 1900 hours of exposure to 8 W CW laser light at a wavelength of 1.48 µm. This submarine optical fiber cable is being employed in a commercial submarine repeaterless transmission system between Okinawa and Miyakojima.