| 摘要 |
PROBLEM TO BE SOLVED: To ensure an effective core diameter of an optical fiber for Raman amplification, using an optical transmission line of which the refractive index is set, corresponding to the light intensity of the exciting light. SOLUTION: In relation to a signal light wavelength, when an optical fiber with a core diameter designed for a fundamental mode is used for Raman amplification, equivalent refractive index of the core is increased due to a strong electric field of the exciting light. In this case, the equivalent refractive index of the core center part is significantly increased. This essentially reduces the core diameter for transmitting the signal light and increases attenuation in the fundamental mode of the signal light. Therefore an optical fiber, of which the refractive index of the core is reduced, in proportion to the intensity distribution in a radius direction of the optical transmission line of the exciting light, is used. COPYRIGHT: (C)2006,JPO&NCIPI |
