Optical waveguides – Optical transmission cable – Loose tube type
Patent
1997-01-27
1998-05-12
Ngo, John
Optical waveguides
Optical transmission cable
Loose tube type
385103, 385104, 385105, 385111, 385113, 385114, G02B 644
Patent
active
057518815
DESCRIPTION:
BRIEF SUMMARY
TECHNICAL FIELD
The present invention relates to a slot-type optical fiber cable comprising a thin and long base body having spiral grooves formed on the outer circumferential surface and a plurality of optical fiber tapes stacked one upon the other within each of the spiral grooves, a plurality of optical fibers being formed within each of the optical fiber tapes, particularly, to an optical fiber cable of a small diameter having optical fibers arranged at a very high density.
BACKGROUND ART
A slot-type optical fiber cable having a plurality of optical fiber tapes stacked one upon the other within spiral grooves formed on the outer circumferential surface of a thin and long base body permits dealing with a relatively large amount of information and, thus, is used nowadays as a relay cable or a subscriber cable for public communication. In recent years, a multi-media system of information is on a sharp increase. Also, diversification of information and increase of the information amount are expected to accompany the spread of the multi-media system. Naturally, the optical fiber cable to be developed is required to be capable of coping with a greater amount of information than in the past.
Further, with increase in the amount of information, the subscriber cable or an optical fiber cable connected between a relay and an individual household is also required to be capable of coping with a greater amount of information. Under the circumstances, the slot-type optical fiber cable is also expected to be used as such an optical fiber.
To be more specific, the slot-type optical fiber cable comprises a long base body having a tension member arranged along the axis thereof and a plurality of optical fiber tapes stacked one upon the other within each of spiral grooves formed along the outer circumferential surface of the base body. For example, four optical fiber tapes are stacked one upon the other within each spiral groove. The outer surface of the base body having the optical fiber tapes arranged within the spiral grooves is wound with a holding tape. Further, a sheath is arranged to cover the outer circumferential surface of the resultant structure. In general, the base body is formed of a high density polyethylene in view of the workability, mechanical properties and cost.
The simplest means to permit the optical fiber cable to be capable of coping with an increased amount of information is to increase the number of optical fibers, or the number of optical fiber tapes, mounted within the optical fiber cable. Naturally, an increase in the number of optical fiber tapes mounted within the optical fiber cable results in an increased outer diameter of the cable. An increase in the outer diameter of the cable gives rise to difficulties. For example, the cable is unlikely to be bent, with the result that, in arranging the cable within a cable passageway, the cable fails to be arranged within the passageway. Also, it is necessary to newly design tools, etc. to meet the increased outer diameter of the cable. It follows that, in order to increase the number of optical fiber tapes arranged within the optical fiber cable, it is necessary to improve the construction of the optical fiber tape itself such that the tapes can be arranged within the optical fiber cable in a higher density.
As a means for improving the construction of the optical fiber tape, it is proposed to decrease the thickness of a resin coating layer having a plurality of optical fibers embedded therein. The conventional optical fiber tape arranged within a slot-type optical fiber cable comprises four optical fibers and a resin layer formed to cover collectively the four optical fibers. These optical fibers, each having a coating layer and a diameter of, for example, 125 .mu.m, are arranged side by side. In general, the resin layer has a thickness, i.e., distance between the outer surface of the resin layer and the outer surface, which faces the outer surface of the resin layer, of the coated optical fiber, of 120 to 150 .mu.m. To be more specific, it is
REFERENCES:
patent: 5193134 (1993-03-01), Pizzorno et al.
patent: 5561730 (1996-10-01), Lochkovic et al.
patent: 5638478 (1997-06-01), Iwakura et al.
patent: 5661836 (1997-08-01), Sano et al.
Microfilm of the specification and drawings annexed to the written application of Japanese Utility Model Application No. 171969/1987 (Laid-Open No. 103814/1989) (Sumitomo Electric Industries, Ltd.) Jul. 13, 1989.
Ishii Nobuhisa
Konda Eiji
Matsuoka Ryuichi
Furukawa Electric Co. Ltd.
Ngo John
LandOfFree
Optical fiber cable does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Optical fiber cable, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Optical fiber cable will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-991794