| 摘要 |
PROBLEM TO BE SOLVED: To provide an optical amplifier of high output and low noise. SOLUTION: The incident signal light is made incident on a first optical fiber 1 excited with the exciting light from a first excitation light source 3, and then amplified, and made incident on a first port of an optical circulator 6 together with the excitation light. The signal light and excitation light are reflected on a first fiber grating 7 of a second port while spontaneously emitted light transmits and absorbed by a non-reflective terminator 5. The signal light and excitation light are made incident on a second optical fiber 2 of a third port from the second port, with the excitation light allowing only the signal light to be amplified for high output. The excitating light from a second excitation light source 4 which excites the second optical fiber 2 is reflected on a second fiber grating 8 of a fourth port 14 from a third port 13, with spontaneously emitted light transmitting for absorption in the non-reflective terminator 5. The excitating light is made incident on the first optical fiber 1 of the first port from the fourth port for excitation, while no spontaneously emitted light saturated for low noise. |
