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Performance Evaluation of an All-optical Automatic Gain-controlled Erbium-doped Fiber Amplifier for Suppression of Signal Fluctuation in Terrestrial Free-space Optical Communication Systems

자유 공간 광통신 시스템에서 신호 변동 억제를 위한 전광 자동 이득 조절 어븀 첨가 광섬유 증폭기의 성능 평가

  • 정유석 (PGM2 연구소, LIG Nex1) ;
  • 김철한 (서울시립대학교 전자전기컴퓨터공학부)
  • Received : 2022.03.23
  • Accepted : 2022.04.13
  • Published : 2022.06.25

Abstract

We have evaluated the performance of an all-optical automatic gain-controlled (AGC) erbium-doped fiber amplifier (EDFA) to suppress the optical signal fluctuation induced by atmospheric turbulence in terrestrial free-space optical communication systems. In our measurements, the input power into the EDFA was set to be -30 dBm and -10 dBm to operate the amplifier in the small-signal and saturation regions, respectively. The fluctuations in the optical signal were emulated with an acousto-optic modulator driven with a sinusoidal voltage. From the measured results, we have found that an all-optical AGC EDFA could suppress the optical signal fluctuation effectively, as long as the EDFA operated in the small-signal region with a high feedback amplified spontaneous emission (ASE) power.

자유 공간 광통신 시스템에서 발생하는 대기 외란에 의한 광신호 변동을 억제하기 위하여 전광(all-optical) 자동 이득 조절(automatic gain controlled, AGC) 어븀 첨가 광섬유 증폭기(erbium-doped fiber amplifier, EDFA)를 활용할 때의 성능을 실험적으로 평가하였다. EDFA에 입력되는 광신호 입력을 -30 dBm과 -10 dBm으로 각각 설정하여 증폭기가 소 신호 영역과 포화 영역에서 동작할 때의 성능을 실험적으로 비교하였다. 이 때 광신호의 요동은 음향 광학 변조기(acousto-optic modulator, AOM)를 활용하여 구현하였다. 실험 결과로부터 EDFA가 소 신호 영역에서 동작하며, 피드백되는 증폭된 자발 방출(amplified spontaneous emission, ASE) 광 전력이 0 dBm으로 증폭기를 포화시킬 수 있는 경우에 가장 작은 광신호 요동 특성을 얻을 수 있음을 확인하였다.

Keywords

Acknowledgement

이 논문은 2019년도 서울시립대학교 연구년교수 연구비에 의하여 연구되었음.

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