Korean Journal of Optics and Photonics (한국광학회지)

Optical Society of Korea (한국광학회)
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Pulse Broadening and Intersymbol Interference of the Optical Gaussian Pulse Due to Atmospheric Turbulence in an Optical Wireless Communication System

광 무선통신시스템에서 대기 교란으로 인한 광 가우시안 펄스의 펄스 퍼짐과 부호 간 간섭에 관한 연구

  • Jung, Jin-Ho (School of Electrical and Telecommunication Engineering, Hoseo University)
  • 정진호 (호서대학교 전기정보통신공학부)
  • Published : 2005.10.01
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Abstract

When an optical pulse propagates through the atmospheric channel, it is attenuated and spreaded by the atmospheric turbulence. This pulse broadening produces the intersymbol interference(ISI) between adjacent pulses. Therefore, adjacent pulses are overlapped, and the bit rates and the repeaterless transmission length are limited by the ISI. In this paper, the ISI as a function of the refractive index structure constant that presents the strength of atmospheric turbulence is found using the temporal momentum function, and is numerically analyzed fer the basic SONET transmission rates. The numerical results show that ISI is gradually increasing at the lower transmission rate than the OC-192(9.953 Gb/s) system and is slowly converging after rapid increasing at the higher transmission rate than the OC-768(39.813 Gb/s) system as the turbulence is stronger. Also, we know that accurate information transmission is possible to 10[km] at the OC-48(2.488 Gb/s) system under any atmospheric turbulence, but is impossible under the stronger turbulence than $10^{-14}[m^{-2/3}]$ at the 100 Gb/s system, $10^{-13}[m^{-2/3}]$ at the OC-768 system, and $10^{-12}[m^{-2/3}]$ at the OC-192 system, because the ISI is seriously induced.

광 펄스가 대기 채널을 통해 전송될 때, 광 펄스는 대기 교란에 의해 감쇄되고 퍼지게 된다. 이러한 펄스 퍼짐이 인접 펄스간의 부호 간 간섭을 일으키고, 그 결과 인접한 펄스들은 중첩이 되어 비트전송률 및 무중계 전송거리를 제한하게 된다. 이에, 본 논문에서는 시간적 모멘트 함수를 이용하여 대기 교란상태에서 부호 간 간섭을 교란 상태를 나타내는 굴절률 구조상수로 구하고, SONET 광 전송방식에서 교란상태에 따른 부호 간 간섭을 수치해석하였다. 그 결과, 교란 정도가 심할수록 부호 간 간섭은 OC-192(9.953 Gb/s) 시스템 이하의 전송률에서는 점차적으로 증가하나, OC-768(39.813 Gb/s) 시스템 이상의 전송률에서는 급격히 증가 후 서서히 수렴함을 알 수 있었다. 또한, OC-48(2.488 Gb/s) 시스템에서는 어떠한 교란상태 하에서도 10 [km] 정도까지 정확한 정보 전송이 가능하나, 100 Gb/s 시스템에서는 $10^{-14}[m^{-2/3}]$ 이상, OC-768 시스템에서는 $10^{-13}[m^{-2/3}]$이상, OC-192 시스템에서는 $10^{-12}[m^{-2/3}]$ 이상의 교란상태에서 심한 부호 간 간섭이 발생하여 정확한 정보 전송이 불가능함을 알 수 있었다.

Keywords

References

  1. Isaac I. Kim, Joseph Koontz, Harel Hakakha, Prasanna Adhikari, Ron Stieger, Carter Moursund, Micah Barclay, Alyssa Stanford, Richard Ruigrok, John Schuster, and Eric Korevaar, 'Measurement of scintillation and link margin for the $TerraLink^{TM}$ laser communication system,' Proc. of SPIE The Int. Soc. for Opt. Eng., vol. 3232, pp. 100-118, 1998
  2. J. Lesh, 'Free space laser communications,' The IEEE conference on Lasers and Electro Optics(CLEO) '99, pp. 316, 1999
  3. M. A. AI-Habash, L. C. Andrews, and R. L. Phillips, 'Mean Fade Time of an Optical Communication Channel Under Moderate- To-Strong Atmospheric Turbulence,' Proc. of SPIE The Int. Soc. for Opt. Eng., vol. 3914, pp. 468-476, 2000
  4. Christopher C. Davis, and Igor I. Smolyaninov, 'The Effect of Atmospheric turbulence on Bit-Error-Rate in an On-Off-Keyed Optical Wireless System,' Proc. of SPIE The Int. Soc. for Opt. Eng., vol. 4489, pp. 126-137, 2002
  5. Timothy L. Grotzinger, 'The effects of atmospheric conditions on the performance of free-space infrared communications,' Proc. of SPIE Free-Space Laser Communication Technologies III, vol. 1417, pp. 484-495, 1991 https://doi.org/10.1117/12.43778
  6. I. Sreenivasiah and Akira Ishimaru, 'Two-frequency mutual coherence function and pulse propagation in a random medium: An analytic solution,' Appl. Optics, vol. 18, no. 10, pp. 1613-1618, 1979 https://doi.org/10.1364/AO.18.001613
  7. C. Y. Young, A. Ishimaru, and L. C. Andrews, Twofrequency mutual coherence function of a Gaussian beam pulse in weak optical turbulence: an analytic solution,' Appl. Opt., vol. 35, no. 33, pp. 6522-6526, 1996 https://doi.org/10.1364/AO.35.006522
  8. Cynthia Y. Young, Larry C. Andrews, and Akira Ishimaru, 'Time-of-arrival fluctuations of a space-time Gaussian pulse in weak optical turbulence: an analytic solution,' Appl. Opt., vol. 37, no. 33, pp. 7655-7660, 1998 https://doi.org/10.1364/AO.37.007655
  9. C. H. Liu and K. C. Yeh, 'Pulse spreading and wandering in random media,' Radio Sci. 14, pp. 925-931, 1979 https://doi.org/10.1029/RS014i005p00925
  10. C. H. Liu and K. C. Yeh, 'Propagation of pulsed beam waves through turbulence, cloud, rain, or fog,' J. Opt. Soc. Am., vol. 67, no. 9, pp. 1261-1266, 1977 https://doi.org/10.1364/JOSA.67.001261
  11. Sherman Karp, Robert M. Gagliardi, Steven E. Moran, and Larry B. Stotts, Optical Channels, Plenum Press, New York, 1988
  12. Akira Ishimaru, Wave Propagation and Scattering in Random Media, vol. 1-2, Academic Press, Inc., 1978
  13. V. I. Tatarski, Wave Propagation in a Turbulent Medium, McGraw-Hill, New York, 1961
  14. Shin Tsy Hong, I. Sreenivasiah, and Akira Ishimaru, 'Plane Wave Pulse Propagation Through Random Media,' IEEE Trans. on Antennas and Propagation, vol. AP-25, no. 6, pp. 822-828, 1977 https://doi.org/10.1109/TAP.1977.1141689
  15. Deborah E. Kelly, Cynthia Y. Young, and Larry C. Andrews, 'Temporal broadening of ultrashort space-time Gaussian pulses with applications in laser satellite communication,' Proc. of SPIE The Int. Soc. for Opt. Eng., vol. 3266, pp. 231-240, 1998
  16. Masaki Amemiya, 'Pulse Broadening due to Higher Order Dispersion and its Transmission Limit,' IEEE J. Lightwave Tech., vol. 20, no. 4, pp. 591-597, 2002 https://doi.org/10.1109/50.996578
  17. S. K. Ramesh, C. A. Goben, V. Aalo, and O. Ugweje, 'Modeling and Evaluation of Intersymbol Interference (lSI) in Coherent Optical Communications,' Proc. of SPIE Coherent Tech. in Fiber Optic Systems, vol. 568, pp. 32-39, 1985