PURPOSE: To decrease the resin amt. while keeping low transmission loss, wide transmission range and easy connection and to transmit light from UV rays to near IR rays with low loss while keeping heat resistance and the like by increasing the diameter only at a part of a refractive index distribution type optical fiber.
CONSTITUTION: This refractive index distribution type optical fiber consists of a noncrystalline fluorine-contg. polymer having substantially no C-H bonds as a matrix. A part of the fiber is made to have a large core diameter while the other part of the fiber has a smaller diameter. Although the smaller core diameter gives the wider transmission range, the fiber is formed to have 10-500μm diameter, and preferably 100-200μm, considering the fiber strength. The both ends of the fiber are formed to have a larger diameter than the other part and the size is not limited. However, the diameter at both ends is preferably 125-1000μm considering easy connection with other fibers. It is preferable that the core diameter R1 at both ends and the diameter R2 at the other part satisfy R1=125 to 1000μm, R2=10-500μm, and R1>R2.
MUROFUSHI HIDENOBU
SUGIYAMA TOKUHIDE
MIYAKE HARUHISA
