| 摘要 |
PURPOSE:To reduce in size and cost an optical fiber amplifier by forming two isolators having no polarization dependence and installed at front and rear sides of an Er-doped fiber of one isolator unit. CONSTITUTION:An isolator unit has an isolator 21 having no polarization dependence, an array 22 held at a predetermined interval at fibers 27, 29, and an array 25 held at one ends of filters 28, 30 at a predetermined interval, a lens 23 for introducing signal lights irradiated from one ends of the fibers 27, 29, and a lens 24 for condensing the light irradiated from the isolator 21 to one ends of the fibers 28, 30. It is used instead of two isolators to be mounted at front and rear sides of the fiber 28. |
