| 摘要 |
PROBLEM TO BE SOLVED: To provide an optical amplifier that can keep optical transmission without deteriorating the transmission quanlity of a signal, even when some of a plurality of laser units comprising an excitation light source goes out of order. SOLUTION: An HPU 30 combines a plurality of laser lights with different oscillation central wavelengths to obtain excitation lights and outputs them, and the HPU 30 is provided with laser units LD 1 to LD 6, and laser units LD 7 and LD 8 that have respectively an oscillation central wavelength with the shortest wavelength and an oscillation central wavelength with the longest wavelength. Thus, when the output of at least one among a plurality of laser lights is stopped as a result of the detection of failure or decreased output, etc., the power of laser lights other than the stopped laser light is changed, to ensure desired amplification and desired gain, and the laser units LD 7 and LD 8 are operated, as necessary. |
