| 摘要 |
PROBLEM TO BE SOLVED: To improve the gain and excitation efficiency. SOLUTION: An optical fiber 1 as the gain medium of a Raman amplifier is excited by an excitation light source 2, the excitation light from the excitation light source 2 and the signal light are multiplexed in a multiplexer 3, and the excitation light after passing the optical fiber 1 is reflected by a reflector 4 for the excitation light. The excitation light source 2 is equipped with wavelength multipleyed laser diodes LD 11 of wavelengths (λS1, λS2, λS3), fiber gratings FG 12 to narrow the oscillation wavelength of each LD 11, and wavelength selection multiplexer WSC to multiplex the excitation light having a plurality of wavelengths, and isolator 14 to remove external residual reflected light. The reflector 4 for excitation light transmits the signal light with low transmission loss while reflects the excitation light at high reflectance to make the light enter again the optical fiber 1. Thus, the total input power of the excitation light can be increased. |
