| 摘要 |
PURPOSE:To obtain an optical fiber loop for excitation of an optical amplifier which causes very little a microbending loss or a loss depending on a polarized light. CONSTITUTION:In an optical amplifier amplifying a signal light 101 by a stimulated emission light obtained by making the signal light 101 and an excitation light enter an optical fiber 1 for excitation doped with a rare-earth element, an optical fiber loop for excitation is constructed in such a manner that the optical fiber 1 for excitation is wound in the shape of a loop in a free space, so as to form a bundle, and a part or the whole of the loop is bonded by a bonding agent 2 so that the bundle be fixed. Since the center of the optical fiber loop for excitation is located in the free space not containing a support such as a bobbin, no lateral pressure is applied to the optical fiber loop 1. By using this optical fiber loop for excitation, therefore, the optical amplifier which is free from a change in the state of a polarized light, causes very little a loss depending on the polarized light and has a stable amplification factor can be constructed. |
