| 摘要 |
PROBLEM TO BE SOLVED: To provide a control method for the optical spectrum analyzer and the optical amplifier to detect a wavelength number and a power of each wavelength in the wavelength division multiplex optical communication system. SOLUTION: An optical switch 1 segments a WDM signal light 1 in a pulse form and the pulse light is given to an optical circulator 3 and made incident into plural fiber gratings 4 connected in series and having different Bragg wavelengths. Since a propagation time difference is produced depending on a difference from a reflecting point coming from the wavelength, the WDM signal lights 1 reflected from the plural fiber gratings 4 are optical pulses arranged in a time base direction. The number of wavelengths is measured by counting the number of the pulses. Furthermore, an exciting power of an optical amplifier is controlled by using the information of the number of wavelengths to make the amplification factor control independently of the number of wavelengths. |
