| 摘要 |
PURPOSE:To obtain a higher gain coefft. as an optical fiber amplifier by adding active ions more in the part in a core where the power density is high thereby giving a difference in the effective concn. of the effective active ions. CONSTITUTION:Not such the fiber B that has an effective concn. of the effective active ions of rare earth elements, etc., capable of making contribution to optical amplification as to be uniform over the entire part of the core but the fiber A having such an effective concn. as to be distributed stepwise or smoothly is formed. Transition metals, etc., in addition to the rare earth elements, such as Er and Nd (neodymium) are included as the elements to be usable as the active ions. The power of the exciting light in the core is small and since the effective concn. of the effective active ions in the part where the optical amplifi cation ability is relatively low can be thereby lowered, the absorption of the signal light by the rare earth elements Er, etc. in this part decreases. The optical fiber having the good optical amplification characteristics is obtd. in this way. |
