| 摘要 |
PURPOSE:To block the wavelength component of the signal light included in pumping light by totally reflecting the signal light by a total reflecting film, then making this light incident on a multiplexing film, multiplexing the light with the pumping light and making the light incident on an Er-doped optical fiber. CONSTITUTION:Filter films 56, 58 which reflect the wavelength component of the signal light and allow the transmission of the pumping light are disposed on at least one of the boundary faces of the optical parts disposed nearer the pumping light side than the multiplexing film 45 for multiplexing the signal light and the pumping light and the air to totally reflect the signal light by the total reflecting film 44 and to make this light incident on the multiplexing film 45. This light is multiplexed with the pumping light and is made incident on the Er-doped optical fiber 52. The wavelength component of the signal light included in the pumping light is blocked at the high attenuation rate corresponding to the number of insertion of the filter films, by which the SN of the signal light is improved. |
