| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To provide an optical fiber capable of achieving wavelength conversion and widening the bandwidth, such as OPA. <P>SOLUTION: In the average zero dispersion wavelengthλ<SB>0</SB>in the overall length of the optical fiber 10, the absolute value of the fourth-stage derivative valueβ<SB>4</SB>of the propagation constantβby the frequencyωis 5×10<SP>-56</SP>s<SP>4</SP>/m or smaller, and the dispersion of the zero dispersion wavelength along the longitudinal direction is±0.6 nm or smaller in the overall length. The optical fiber 10 comprises at least a central core part 11 having the maximum refractive index N<SB>1</SB>and an outside diameter 2a, a depressed part 12 having the minimum refractive index N<SB>2</SB>and an outside diameter 2b, and a clad part 13 having the maximum refractive index N<SB>3</SB>. The refractive index of each part satisfies the relation N<SB>1</SB>>N<SB>3</SB>>N<SB>2</SB>. When the relative refractive index difference of the central core part isΔ<SB>+</SB>, and the relative refractive index difference of the depressed part isΔ<SB>-</SB>, using the refractive index of the clad part as the standard, the differenceΔ<SB>+</SB>-Δ<SB>-</SB>is 2.2% or larger, and the ratio of the outer diameters Ra of the central core part and the depressed part (=2a/2b) is in the range of 0.2-0.7. <P>COPYRIGHT: (C)2007,JPO&INPIT</p> |
