| 摘要 |
<p>The present invention relates to an optical filter for flattening the gain spectrum of an optical amplification system (including at least one optical amplifier) inserted in a transmission line for transmitting a plurality of signal light components having wavelengths different from each other, and a transmission system including the optical filter. The optical filter according to the invention has a transmission spectrum with inverse characteristics to those of the gain spectrum of the optical amplification system for amplifying the plurality of signal light components. Particularly, the transmission spectrum of the optical filter is characterized in that, in the second wavelength range narrower than the first wavelength range corresponding to the signal light wavelength range and included in the first wavelength range, the difference between the maximum loss and the minimum loss of the transmission spectrum substantially equals the difference between the maximum gain and the minimum gain of the gain spectrum of the optical amplification unit in the first wavelength range.</p> |
