Journal of the Institute of Electronics Engineers of Korea SD (대한전자공학회논문지SD)

The Institute of Electronics and Information Engineers (대한전자공학회)
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Broadband Optical Transmitter using Feedforward Compensation Circuit

피드포워드 보상회로를 이용한 광대역 광송신기

  • Yun, Young-Seol (School of Electrical and Electronic Engineering, Chung-Ang University) ;
  • Lee, Joon-Jae (School of Electrical and Electronic Engineering, Chung-Ang University) ;
  • Moon, Yon-Tae (School of Electrical and Electronic Engineering, Chung-Ang University) ;
  • Kim, Do-Gyun (School of Electrical and Electronic Engineering, Chung-Ang University) ;
  • Choi, Young-Wan (School of Electrical and Electronic Engineering, Chung-Ang University)
  • 윤영설 (중앙대학교 전자전기공학부) ;
  • 이준재 (중앙대학교 전자전기공학부) ;
  • 문연태 (중앙대학교 전자전기공학부) ;
  • 김도균 (중앙대학교 전자전기공학부) ;
  • 최영완 (중앙대학교 전자전기공학부)
  • Published : 2007.04.25
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Abstract

Linearity is the one of the most important features for analog-optic transmission system. In our research, the available bandwidth for the feed-forward compensation circuit is enhanced by using a 180 hybrid coupler in the circuit. The bandwidth having the decreased 3rd-order intermodulation distortion(IMD3) over 10 dB is extended over 200 MHz with the center frequency of 1.6 GHz. We performed an efficient bandwith measurement for the feed-forward compensation system, which uses the network analyzer instead of the traditional measuring system that uses two RF signal generators and the spectrum analyzer. We identify the usefulness of this method from experimental results. In this study, we used cheap digital-purpose laser diodes for economical aspect, which proves the efficiency of the proposed analog system. The spurious-free dynamic range is improved about 6 dB/Hz.

아날로그 광전송 시스템의 성능평가에 있어 광송신기의 선형성은 매우 중요한 파라미터이다. 본 논문에서는 피드포워드 보상회로를 적용한 광송신기에서 180도 하이브리드 커플러를 사용하여 위상천이기의 좁은 주파수 반응으로 인해 제한되었던 보상 대역폭을 확장한 새로운 방식의 광대역 아날로그 광송신기 특성에 대해 보고한다. 3차 혼변조 왜곡신호의 크기가 10 dB 이상 감소되는 보상 대역폭이 1.6 GHz를 중심으로 약 200 MHz 까지 확장됨을 확인하였다. 보상기법을 적용한 회로의 대역폭 측정은 네트워크 분석기를 활용하여 효율적으로 수행하였으며, 측정결과를 통해 그 효용성을 입증하였다. 디지털용으로 사용되는 저가의 레이저 다이오드를 사용하여 SFDR (Spurious-Free Dynamic Range)이 약 6 dB/Hz 개선됨을 실험적으로 확인하여 본 연구의 유효성을 검증하였다.

Keywords

References

  1. J. E. Mitchell, 'Performance of OFDM at 5.8GHz using radio over fibre link,' Electronics Letters, vol.40, no.21, pp. 1353-1354, Oct. 2004 https://doi.org/10.1049/el:20046724
  2. J. C. Daly,'Fiber Optic Intermodulation Distortion,' IEEE Trans. On Communications, Vol. COM-30, No. 8, pp.1954 1958, Aug. 1982
  3. R. B. Childs and V. A. O'Byrne, 'Predistortion linearization of directly modulated DFB lasers and external modulators for AM video transmission', in OFC '90, paper WH6, 1990
  4. L. S. Fock, A. Kwan, and R.S.Tucker, 'Reduction of Semiconductor Laser Intensity Noise by Feedforward Compensation:Experimental and Theory,' IEEE Journal of Lightwave Technology, Vol.10, No.12, pp.1919 1925, DEC. 1992 https://doi.org/10.1109/50.202819
  5. D. Hassin and R. Vahldieck, 'Feedforward Linearization of Analog Modulated LDs- Theoretical Analysis and Experimental Verification,' IEEE Trans. On MTT, Vol.14, No.12, pp. 2376 2382, DEC. 1993 https://doi.org/10.1109/22.260731
  6. L. S. Fock and R. S. Tucker, 'Reduction of Distortion in analogue modulated semiconductor lasers by feedforward compensation,' Electron. Lett., vol. 27, pp. 669-671, 1991 https://doi.org/10.1049/el:19910419
  7. L. S. Fock, R. S. Tuck, 'Simultaneous reduction of intensity noise and dirtotion in semiconductor lasers by feedforward compensation,' Elect. Letts. 27, 1297-1299, 1991 https://doi.org/10.1049/el:19910811
  8. T. Ismail, C. P. Liu and A. J. Seeds, 'Uncooled directly modulated high dynamic range source for IEEE802.11a wireless over fibre LAN applications,' Proc of Optical Fibre Communications, (OFC 2004)., Los Angeles, California, 2004
  9. T. Ismail, C. P. Liu, J. E. Mitchell, and A. J. Seeds, 'Feed-Forward Linearised Uncooled DFB Laser in a Multi-Channel Broadband Wireless over Fibre Transmission at 5.8 GHz,' International Tropical Meeting on Microwave Photonics (MWP) 2005, T3-6, pp. 115-118, October 2005
  10. Sang-Hyun Park, and Young-Wan Choi, 'Significant Suppression of the Third Intermodulation Distortion in Transmission System with Optical Feedforward Linearized Transmitter,' IEEE Photonics Technology Letters, vol. 17, pp. 1280-1282, Jun. 2005 https://doi.org/10.1109/LPT.2005.846460
  11. Joon-Jae Lee, Sang-Hyun Park, and Young-Wan Choi, 'Enhanced ACPR of W-CDMA Signals Optical Feedforward Transmitter by Optimization,'Microwave Photonics 2005, pp 59-62, Oct. 2005