320 Gbps WDM 전송 시스템에서 광 위상 공액기의 위치에 따른 비트 에러율 특성

Characteristics of Bit Error Rate dependence on the Position of Optical Phase Conjugator in 320 Gbps WDM System

  • 이성렬 (목포해양대학교 해양전자통신공학부)
  • 발행 : 2005.08.01

초록

장거리 $8{\times}40$ Gbps 파장 분할 다중 시스템에서 색 분산과 자기 위상 변조에 의해 왜곡된 광 펄스를 최상으로 보상할 수 있는 최적의 광 위상 공액기 (OPC ; Optical Phase Conjugator)의 위치를 수치적 방법으로 살펴보았고, 이 위치에서의 전체 채널의 눈 열림 패널티 (EOP ; Eye Opening Penalty)와 비트 에러율 (BER ; Bit Error Rate) 특성을 OPC가 전체 전송 거리의 중간에 위치한 경우 (MSSI ; Mis-Span Spectral Inversion)와 비교해 살펴보았다. 먼저 OPC를 이용해 왜곡된 광 신호를 보상하는 WDM 시스템에서 모든 채널의 최상의 보상을 수행하기 위해서는 전송하고자 하는 변조 파형의 형식과 광섬유 분산 계수와 관련하여 OPC의 위치가 전체 전송 거리의 중간이 아닌 다른 곳으로 이동되어야만 하는 것을 확인할 수 있었다. 아울러 최적 OPC 위치를 갖는 WDM 시스템을 이용한 경우 수신측에서의 광 신호의 EOP 특성은 채널에 따라 다소 차이가 있을 수 있지만, BER 특성은 거의 동일하다는 것을 확인할 수 있었다.

In this paper, optimal position of optical phase conjugator (OPC) for best compensating distorted WDM channels due to both chromatic dispersion and self phase modulation (SPM) in $8{\times}40$ Gbps WDM systems is numerically investigated, and the eye opening penalty (EOP) and bit error rate (BER) characteristics of overall WDM channels at this position is investigated, comparing with that in case of OPC placed at mid-way of total transmission length. It is confirmed that the compensation extents in WDM system with OPC is more improved by the shifting OPC position from the mid-way of total transmission length, depending on the modulation format and fiber dispersion coefficient. Ant it is confirmed that, from a viewpoint of the reception performance, EOP of each channel is more or less different with one another, but the BER characteristics of overall channels are almost equal.

키워드

참고문헌

  1. P. V. Mamysheva and N. A. Mamysheva, Pulse-overlapped dispersion-managed data transmission and interchannel four-wave mixing' , Opt. Lett., Vol. 24, pp. 1454-1456, Nov. 1999 https://doi.org/10.1364/OL.24.001454
  2. A. Yariv, D. Fekete, and D. M. Pepper, 'Compensation for channel dispersion by nonlinear optical phase conjugation', Opt. Lett., Vol. 4, pp. 52-54, 1979 https://doi.org/10.1364/OL.4.000052
  3. S. Watanabe et al., Generation of optical phase-conjugate waves and compensation for pulse shape distortion in a single-mode fiber , J. Lightwave Technol., Vol. 12, No. 12, pp. 2139-2145, 1994 https://doi.org/10.1109/50.350616
  4. W. Pieper et al., 'Nonlinearity-insensitive standard-fiber transmission based on optical- phase conjugation in a semiconductor-laser amplifier', Electron. Lett., Vol. 30, pp. 724-726, 1994 https://doi.org/10.1049/el:19940494
  5. S. Watanabe and M Shirasaki, 'Exact compensation for both chromatic dispersion and Kerr effect in a transmission fiber using optical phase conjugation', J. Lightwave Technol., Vol. 14, No.3, pp. 243-248, 1996 https://doi.org/10.1109/50.485581
  6. I. Brener et al., 'Cancellation of all Kerr nonlinearities in long fiber spans using a $LiNbO_3$ phase conjugator and Raman amplification', in Optical Fiber Communications (OFC) Conf. 2000, pp. 266 - 268
  7. G. P. Agrawal, Nonlinear Fiber Optics Academic Press, 2001
  8. F. Forghicri, R. W. Tkach and A. R. Chraplyvy, 'WDM systems with unequally spaced channels', J. Lightwave Technol., Vol. 13, No.5, pp. 889-897, 1995 https://doi.org/10.1109/50.387806
  9. G. P. Agrawal, Fiber-optic communication systems, John Wiley & Sons, Inc., 2002
  10. K. Inoue, 'Four-wave mixing in an optical fiber in the zero-dispersion wavelength region', J. Lightwave Technol., Vol. 10, No. 11, pp. 1553 -1561, 1992 https://doi.org/10.1109/50.184893
  11. Seong-Real Lee and S. E. Cho, 'Pump light power of wideband optical phase conjugator using HNL-DSF in WDM systems with MSSI', 한국통신학회논문지, 제 30권 3A호, pp. 168-177, 2005
  12. S. Kawal and K. Iwatsuki, 'System design of filter-guided soliton transmission considering amplitude noise and timing jitter', J. Lightwave Technol., Vol. 16, No. 12, pp. 2347-2354, 1998 https://doi.org/10.1109/50.736601
  13. N. A. Olsson, 'Lightwave systems with optical amplifiers', J. Lightwave Technol., Vol. 7, No.7, pp. 1071-1082, 1989 https://doi.org/10.1109/50.29634
  14. Seong-Real Lee and Hwang-Bin Yim, 'Compensation characteristics dependence on the position of optical phase conjugator in 320 Gbps WDM system', J. of the Korean Electromagne. Eng. Soc., Vol. 4, No.4, pp. 162-167, 2004
  15. C. Lorattanasane and K. Kikuchi, 'Design theory of long-distance optical transmission systems using midway optical phase conjugation', J. Lightwave Technol., Vol. 15, No.6, pp. 948 - 955, 1997 https://doi.org/10.1109/50.588664