| 摘要 |
PURPOSE: To enable an optical amplifier to amplify an ordinary laser signal with a high gain and to be effectively used for a signal line by composing an active optical fiber of doped amplification and attenuation cores and optically connecting both the cores in a prescribed wavelength band. CONSTITUTION: An active optical fiber 6 is composed of an amplification core 11 and an attenuation core 12, the amplification core 11 is doped by erbinium, etc., for example, and the attenuation core 12 contains a material for absorbing optical energy. These two cores 11 and 12 are included in the area of laser radiation wavelength of the core 11 and optically connected in the wavelength band different from a transmission signal band. The signal of a signal radiation laser 2 is inputted from one terminal of the amplification core 11 and a pump laser signal 5 is inputted to a coupler 3. Thus, noise is reduced by the core 12 and a laser emitter signal 2 is amplified with the high gain to be effectively used for the communication line. |
