| abstract |
A fiber optic amplifier includes a pump light source (107, 108) producing pump light and an optical amplifier medium in which signal light is amplified by means of the pump light. An optical filter (105, 106) selectively transmits the pump light and selectively reflects light having a wavelength bandwidth equal to that of the signal light. Two fiber optic amplifiers (103, 104), joined by means of a 4 terminal, full flow optical circulator (102) amplify the upstream signal light and the downstream signal light. The signal light and the amplified signal light constitute an input for, and an output of, the optical fiber amplifier (103, 104). |