PURPOSE: To improve mechanical strength and space factor and to facilitate the normalization of positions by the grooves on the outside circumference and the discrimination of fibers by disposing plural pieces of optical fibers in parallel along the axial direction, and sticking only the mutually adjacent parts by melt-sticking.
CONSTITUTION: Plural pieces of optical fibers 23aW23c consisting of cores 21aW21c and clads 22aW22c are disposed in parallel along their axial direction, and only the mutually adjacent parts 24aW24c are melt-stuck, whereby plural grooves 26aW26c along the axial direction are formed on the outside circumference. Then, the fibers hardly receive deformation, and high strength is retained despite the reduction of the diameters of the respective fibers. If the grooves on the outside circumference are utilized, axial alignment is easy in connection. The shape may be a flat shape or a star shape as shown in figure 4. If necessary, a dummy fiber of glass material is used for the central fiber 31.
MAEKAWA EIJI
NIHEI FUMIHIRO
HATANO TOKIJI
NAGASAWA SHINJI
