| 摘要 |
PROBLEM TO BE SOLVED: To obtain an optical fiber for laser capable of oscillating a laser beam of high output by constituting the optical fiber of plural cores added with rare earth elements and a common clad enclosing these plural cores. SOLUTION: The optical fiber is provided with plural cores 1 consisting of quartz glass added with rare earth elements. The arrangement of the plural cores 1 includes the proper arrangement of the cores in one common clad and the line-up of the plural cores 1 in one row within the common clad 2. The cores 1 consist of glass which is formed by doping the rare earth elements, such as Nd and Er to glass, such as quartz glass and fluoride glass to enable the formation of an inversion distribution. The common clad 2 consists of glass, such as pure quartz glass and fluorine-doped quartz glass and has the refractive index lower than the refractive index of the glass of the cores 1. The sectional shape thereof is rectangular. The outer periphery of the common clad 2 is provided with a supporting layer 3 and further, this supporting layer 3 is coated with a coating layer 4. |
