| 摘要 |
PROBLEM TO BE SOLVED: To provide an auxiliary light source in wavelength division multiplex for covering many channels with fewer auxiliary light sources at a low cost by combining existing parts without using new devices, and making a restoring time short. SOLUTION: An optical pulse with four or longer wavelengths at intervals of equal wavelength to each other is generated from a WDM light source by using outer modulators EM1 to EM4. When a defective light source is detected, the remaining wavelengths of the normal light sources are combined to generate a four light-wave mixed light beam, that includes the wavelength of the defective light source. The output light equal to the wavelength of the defective light source is extracted from the four light-wave mixed light beam, and the output light is subjected to injection mode locking through a multiple- longitudinal mode oscillation laser to cause the light beam to oscillate in a single mode. |
