| 摘要 |
PROBLEM TO BE SOLVED: To obtain a high gain or high output by a single gate switch, without giving adverse influences on the transmission characteristics. SOLUTION: A signal light of 1550 nm wavelength is inputted at a light intensity of -10 dBm to an Er doped fiber(EDF) 11 via an optical transmission line 100, while an exciting light of 1480 nm wavelength from an exciting light source 31 to an optical transmission line 105 is inputted to the EDF 11 via an optical branch 52, the light signal is optically amplified by the EDF 11 and inputted to an EDF 12 via an optical isolator 21, while the exciting light of 1480 nm wavelength from the exciting light source 32 to an optical transmission line 107 is inputted to the EDF 12 via an optical branch 54, the light signal is optically amplified up to +15 dBm by the EDF 12 and outputted to an optical transmission line 101, the light inputted to the optical transmission line 100 can be outputted from an optical transmission line 104 via an optical transmission line 102 by installing an optical branch 51 on the optical transmission line 100 and the light inputted to the optical transmission line 100 can be outputted at the same time from the optical transmission lines 101, 104. |
