| 摘要 |
PURPOSE:To attain a flat gain wavelength characteristic and to expand an operationable wavelength range by inserting an equalizing optical filter making the gain wavelength characteristic of a rare-earth metal doped optical fiber flat within a wavelength range to a signal input side, or a signal output side or both of the rare-earth metal doped optical fiber. CONSTITUTION:An equalizing optical filter 34 making a gain wavelength characteristic of an amplifier 35 flat within a wavelength range is inserted to a signal input side, or a signal output side or to the both of a rare-earth metal doped optical fiber forming a rare-earth metal doped optical fiber type amplifier 35. The gain wavelength characteristic of the equalizing optical filter 34 is made flat around the wavelength of 1.535mum of, e.g. an Er doped optical fiber amplifier. Thus, the available wavelength operating range is expanded. |
