| 摘要 |
PURPOSE:To maintain gain or output power to a desired fixed value and at the same time, to match a gain peak wavelength with a signal light wavelength, by providing a light amplifier part control means and a variable light attenuation means within a light amplifier. CONSTITUTION:A light amplifier 11 is used in a light amplifier multistage repeating transmission system where a subordinate connection is performed for plural light amplifiers at multistage between transmission and reception terminal stations 14 along an optical fiber 13, has a light amplifier part 25 composed of a rare earth dope fiber, multiplexes exciting light with input signal light, amplifies it and derives output signal light. In this case, the light amplifier 11 is provided with a light amplifier part control means 31 for matching the gain peak wavelength in the system with the wavelengths of input and output signal light and a variable light attenuation means 32 adjusting the level of the signal light power from the light amplifier part 25 and making output signal light to a prescribed signal light power level. In the means 31, the gain peak wavelength can be matched with the signal light wavelength by making exciting light of a proper level incident. |
