| 摘要 |
PROBLEM TO BE SOLVED: To improve excitation efficiency. SOLUTION: To one end of a light amplification fiber 10 to which a rare earth element is added, a wavelength division multiplex(WDM) photocoupler 14 for multiplexing excitation light (wavelength λp) from an excitation light source 12 to signal light to be light amplified, and for supplying it to the light amplification fiber 10, is connected. To the other end of the light amplification fiber 10, an optical fiber grating 16 for selectively reflecting the wavelength λp of the excitation light for 100% or almost 100%, and for transmitting the signal light almost without loss, is connected. At the input part of the signal light to be light amplified, an optical isolator 18 for interrupting light propagated in the opposite direction of the signal light is arranged. |
