| 摘要 |
PURPOSE:To provide an optical fiber amplifier with a large maximum signal light output, a low-noise optical fiber amplifier, or a low-noise optical fiber amplifier with a high signal light maximum output and further a device for measuring amplification characteristics of the optical fiber amplifier which can measure the noise figure of the optical fiber amplifier accurately for the same excitation light input. CONSTITUTION:Excitation light passes through an excitation light source 2a, a first optical multiplexer/demultiplexer 3a, a first rare earth doped optical fiber 4a, a second optical multiplexer/demultiplexer 3a, a second rare earth doped optical fiber 4b in this order and only the second optical multiplexer/ demultiplexer 3b exists between the first and second rare earth doped optical fibers 4a and 4b, thus reducing the loss of one optical multiplexer/demultiplexer as compared with before. In a same signal light input and excitation light input, the excitation light intensity input to the second rare earth doped optical fiber 4b is large, thus obtaining an optical fiber amplifier with a large signal light maximum output. |
