Nippon Telegraph and Telephone Public Corporation

Norio Murata

Mitsutoshi Hoshino

Shinzo Yamakawa

A protective packaging method of protecting the spliced portion of optical fibers, comprising the steps of providing a protective packaging assembly having a heat-shrinkable tube capable of shrinking in the radial direction thereof, an extended form of hot-melt adhesive disposed on the inner side of the heat-shrinkable tube, and an electrical resistance heating element so disposed on the inner side of the heat-shrinkable tube and extendedly in the axial direction of the heat-shrinkable tube as to be capable of heating both the heat-shrinkable tube and the extended form of hot-melt adhesive, and a space provided in the heat-shrinkable tube for allowing the passage of the optical fiber; placing the protective packaging assembly around the splice portion of the optical fiber which has been passed through the space; and supplying electric current through the electrical resistance heating element to heat-melt the hot-melt adhesive and to heat-shrink the heat-shrinkable tube for forming a reinforced unit including the spliced portion of the optical fiber and the electrical resistance heating element with the hot-melt adhesive acting as a sealant inside the heat-shrunk tube. A highly reliable reinforced portion is easily and rapidly formed which does not contain residual bubbles. The reinforced fiber is hardly broken and has little increase of transmission loss.

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Mito, Japan

Norio Murata