LOW DISPERSION OPTICAL FIBER

摘要

PURPOSE: To obtain an optical fiber which is zero or nearly zero in wavelength dispersion by changing a core diameter in such a manner that the wavelength dispersion changes in a range across the part of the core diameter where the wavelength dispersion at a transmission wavelength is positive and the part of the core diameter where the wavelength dispersion is negative. CONSTITUTION: The refractive index distribution shape of the fiber 1 is made into a step index type, a dual type having a stepped core part, etc. The shape at a beginning end 1A and the shape at a terminal 1B are nearly analogous. The core diameter rA at the beginning end 1A of the fiber 1 and the core diameter rB at the terminal 1B are determined. In such a case, the range of the core diameter where the part of the core where the wavelength dispersion is positive and the part of the core diameter where the wavelength dispersion is negaative are continuous is eventually made to exist by properly determining the structure parameter of the single mode fiber. The core diameter rA at the beginning and the core diameter rB at the terminal 1B of the fiber is determined in the range of the core diameter which satisfies this condition. Then, the positive and negative wavelength dispersions generated while the light of the transmission wavelength entering from the beginning end 1A arrives at the terminal 1B are negated to nearly zero.