SLOT FOR CARRYING OPTICAL FIBER

摘要

PROBLEM TO BE SOLVED: To obtain a slot for carrying optical fibers which is constant in curva ture even for grooves having alternately inverting waveforms by providing the slot with the grooves in accordance with a mathematical expression at which the curvature of the inserting portions of the inversion grooves formed on the surface is kept always constant. SOLUTION: The slot for carrying the optical fibers has a long-sized tension member 1 and a coating layer 2 made of a synthetic resin laminated on the outer periphery of this tension member 1. The grooves 3 extending in the axial direction are formed of the alternately inverting waveforms on the outer periphery of the coating layer 2. The waveforms in the pitch inverting parts of the grooves 3 are derived by the mathematical expression: Z"=±1/r0ρ0√(z'2+ r02)√(z'2+r02+r0ρ0)√(z'2+r02-/r0ρ0). In the mathematical expression, z is the function z(θ) in the axial direction of the grooves 3 of the slot for carrying the optical fiber which is defined as z for the purpose of explanation; z'=dz/dθ, z"=d2z/dθ2;θis an inversion angel; r0 is a slot radius;ρ0 is an initial radius of curvature. The curvature of the grooves is constant if such grooves 3 are formed.