| 摘要 |
PROBLEM TO BE SOLVED: To provide a polarization-preserving optical fiber amplifier that performs optical amplification by holding the polarized wave of signal light, can be improved in gain, and can be reduced in noise. SOLUTION: In this optical fiber amplifier, a polarizer 7 is connected between first and second EDFs 4a and 4b. Amplified spontaneous emission light is emitted from the emitting edge of the first EDF 4a together with amplified signal light and made incident to the polarizer 7. The polarizer 7 is positioned so that the polarizer 7 may only transmit the polarized light component parallel to the signal light and the polarized wave component perpendicular to the signal light of the light made incident to the polarizer 7 is removed. Consequently, the polarized wave component perpendicular to the signal light of the spontaneous emission light is removed and the power of the spontaneous emission light can be reduced by half without damping the intensity of the signal light. |
