OPTICAL FIBER AMPLIFIER

摘要

PURPOSE:To obtain an optical fiber amplifier of high gain exceeding the reflection attenuation loss among parts and of low noise by connecting two optical amplification fibers with a circulator and by allowing them to operate in a range where they do not oscillate. CONSTITUTION:Each port of the circulator 1 having four parts is connected optically in order of 1a to 1b to 1c to 1d and to 1a. An input signal optical fiber 6 and an output signal optical fiber 7 are connected to a port 1a and a port 1d respectively. Optical amplification fibers 8a and 8b are connected respectively to ports 1b and 1c via silica fibers 11 in which the amount of the change of refractive index is high. The port of the multiplexed light output of an optical fiber coupler 5 is connected to one side of respective optical amplification fibers 8a, 8b via quartz fibers 11 in which the amount of the change of refractive index is high. A dielectric mult-layer thin film is connected to the optical input port of one side of the fiber coupler 5 as a mirror 10. Further, two semiconductor modules are connected to the optical input port of the other side of the coupler 5 by synthesizing polarized waves.