| 摘要 |
PURPOSE:To increase the insertion interval of an optical amplifier and to obtain a low-cost, high-reliability, and extremely-fast optical transmission line by connecting an optical fiber which has specific group speed dispersion and an optical amplifier which has a specific amplification degree alternately. CONSTITUTION:Optical transmission lines 1 and 2 consisting of many single- mode optical fibers with core diameters f1-f4 are connected through lenses 3 and 4 and the optical amplifier 5. The group speed dispersion kz of the optical fibers varies satisfying kzF<2>(kz)+alphaexp(-2gammaz)=0 in a light propagation direction (axial direction). Here, F(kz) is the core diameter of an optical as a function of kz, (z) the transmission-directional distance of the optical fiber, alpha a constant, and gamma a coefficient of light loss. The optical amplification degree of the optical amplifier 5 is so set that the peak power P of light at all incidence terminals of the plural optical fibers satisfies a relation 0.5Popt<P<1.5Popt. Here, Popt=n0 AE<2>/754; and n0 is the linear refractive index of a core, A is the core area, and E is expressed as shown by II. |
