Optical fiber and method of measuring coefficient of kinetic friction of optical fiber
An optical fiber of the present invention comprising a bare optical fiber and one or plural coating layers on the bare optical fiber, wherein Y, the Young's modulus of the outermost coating layer is in the range of 400 to 1000 and μ, a coefficient of kinetic friction which occurs between the outermost coating layers is equal to or larger than 0.15, and further satisfying the following formulas (a) and (b); μ≦−0.9822 Log Y +3.45156 (a) μ≧−0.5418 Log Y +1.74128, (b) wherein the unit of Y is MPa. By the present invention, optical fibers with a low rate of occurrences of the attenuation discontinuity in a measurement result by OTDR and the method of measuring the coefficient of kinetic friction of optical fiber with high reliability are offered.
1. An optical fiber comprising a bare optical fiber and one or plural coating layers on the bare optical fiber, wherein Y, the Young's modulus of the outermost coating layer, is in the range of 400 to 1000 and μ, a coefficient of kinetic friction which occurs between the outermost coating layers which have been organized respectively in two said optical fibers, is equal to or larger than 0.15, and further satisfying the following formulas (a) and (b);
μ≦−0.9822 Log Y+ 3.45156 (a)
μ≧−0.5418 Log Y+ 1.74128 (b),
wherein the unit of Y is MPa.
2. The optical fiber according to claim 1 , wherein μ further satisfies the following formula (c);
μ≦−0.5418 Log Y+ 1.85912 (c).
3. The optical fiber according to claim 1 , wherein the bare optical fiber is a silica-based optical fiber.
4. The optical fiber according to claim 1 wherein the bare optical fiber has a diameter of 125 μm±5 μm.
5. The optical fiber according to claim 1 including a first coating layer and an outermost coating layer as the coating layers, wherein Young's modulus of the first coating layer is equal to or less than 2 MPa.
6. The method of measuring the coefficient of kinetic friction of optical fiber that is to measure the kinetic frictional force caused by the movement of a sled on a fixed horizontal table under the condition that two optical fibers are fixed parallel to each other on the horizontal fixed table and on the bottom of the sled and the sled is loaded on the fixed table so that each optical fiber cross right-angled, and they contact; wherein a weight of the sled along the optical fiber fixed to bottom of sled is more than 60 gf and less than 110 gf, and tensile speed of moving the sled is more than 100 mm/min and less than 500 mm/min.
7. The method of measuring the coefficient of kinetic friction of optical fiber according to claim 6 wherein weight of sled is more than 70 gf and less than 110 gf.
8. The method of measuring the coefficient of kinetic friction of optical fiber according to claim 6 wherein tensile speed of moving the sled is more than 200 mm/min and less than 500 mm/min.
9. An optical fiber comprising a bare optical fiber and one or plural coating layers on the bare optical fiber, wherein Y, the Young's modulus of the outermost coating layer, is in the range of 400 to 1000 and μ, a coefficient of kinetic friction which occurs between the outermost coating layers, is equal to or larger than 0.15, and further satisfying the following formulas (a) and (b);
μ≦−0.9822 Log Y+ 3.45156 (a)
μ≧−0.5418 Log Y+ 1.74128 (b),
wherein the unit of Y is MPa
wherein a method of measuring the coefficient of kinetic friction of optical fiber that is to measure the kinetic frictional force caused by the movement of a sled on a fixed horizontal table under the condition that two optical fibers are fixed parallel to each other on the horizontal fixed table and on the bottom of the sled and the sled is loaded on the fixed table so that each optical fiber cross right-angled, and they contact; wherein a weight of the sled along with the optical fiber fixed to bottom of sled is more than 60 gf and less than 110 gf, and tensile speed of moving the sled is more than 100 mm/min and less than 500 mm/min.