摘要 |
PROBLEM TO BE SOLVED: To provide a single mode light waveguide fiber designed to restrict a power penalty due to four optics mixtures and a manufacturing method of that waveguide. SOLUTION: A characteristic change such as radius (diameter 83, 84) or refractive index, for example, of a waveguide fiber core gives all divergence along the length of a waveguide. An algebraic summation of multiples of the length and all divergence is controlled to a pre-selected value toward each waveguide constituting a system link. When the size and the small length part of the change of all divergence is properly selected, a system link with which a signal advances by a short distance in a waveguide part having all divergence close to zero is obtained. However, the change of all divergence gives the system link generating a distributed effect pre-selected for the signals in the wavelength range pre-selected. The distributed effect against the signals can be selected to be substantially zero. A veriety of techniques for manufacture of DM fibers is disclosed. |