| 摘要 |
Signal wavelengths lambd1, lambd2, lambd3 of signal light components multiplexed at signal multiplexing sections 31, 41, 51 of multiplexing stations 3, 4, 5 installed on the input end side of an EDFA 2 on an optical transmission line 1 are set such that the wavelength-dependent noise figure of EDFA 2 successively decreases from the signal wavelength lambd1 multiplexed at the signal multiplexing section 31 closest to the input end of EDFA 2 to lambd2 and lambd3. On the other hand, the transmission length of individual signal light component before being fed into the EDFA 2 is the shortest in the signal light component at lambd1 and successively increases at lambd2 and lambd3. Thus, the order of magnitude of input signal light power is the same as the order of highness of noise figure in EDFA 2, whereby fluctuations in S/N ratio in the resulting amplified light are reduced.
|
