Halkasal Hüzmenin Zayıf Okyanussal Türbülansta Bit Hata Oranı

Rytov yöntemine dayalı olarak zayıf bir okyanussal ortamdaki lazer iletişim bağlantısının eksenüzerine ıpıldama indeksi, paralelleştirilmiş halka hüzmesi için formüle edilmiştir. Elde edilen budeğerler kullanılarak, ortalama bit hata oranı (<BER>), log-normal dağılımlı olarak değerlendirilmiştir.Paralelleştirilmiş halkalı hüzmelerin ıpldama indeksleri; sabit birincil kaynak boyutus1  , değişendairesel hüzme kalınlığı, yayılma mesafesi L , kaynak boyutu s  , ortalama karesel sıcaklığın dağılmaoranı T  , sıcaklık ve tuzluluk dalgalanmasının göreli kuvvetini temsil eden boyutsuz parametresiwiçin bulunur. Paralelleştirilmiş halka hüzmesi için kayanak büyüklüğü ve ortalama sinyal gürültü oranı(<SNR>)’ na göre <BER>, birim kütle akışkanı ve kaynak boyutları için türbülans kinetik enerjinin çeşitlidağılım oranı için sergilenmektedir. Belirtilen iletişim bağlantısında, halkasal hüzmelerin ikincil kaynakboyutu sıfıra eşit olduğunda, yani Gaussian hüzmesi olduğunda, <BER> daha fazla avantajsağlayacaktır.

Anahtar Kelimeler:

Okyanussal türbülans, Okyanus optiği, Optiksel haberleşme, ıpıldama

BER OF ANNULAR BEAMS IN WEAK OCEANIC TURBULENCE

Based on Rytov method, on-axis scintillation index of laser communication link in a weakoceanic medium is formulated for collimated annular beam. Employing these obtained scintillationvalues, average bit error rate (<BER>) is evaluated where the intensity has log-normal distribution.Scintillation indices of collimated annular beams are found for fixed primary source sizes1  , varyingannular beam thickness, propagation distance L , source size s  , the rate of dissipation of the meansquared temperature T  , non-dimensional parameter representing the relative strength of temperatureand salinity fluctuation w. <BER> versus the source size and the average signal to noise <SNR> foundfor the collimated annular beams are exhibited for various rate of dissipation of turbulent kinetic energyper unit mass of fluid  and source sizes s  . At the stated link lengths, as secondary source size ofannular beam equals to zero, that is, for Gaussian beam, <BER> will offer more advantages.

Keywords:

Oceanic turbulence, Ocean optics, Optical communication, Scintillation,

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Andrews, L. C., Phillips, R. L., Hopen, C. Y., 2001, Laser Beam Scintillation with Applications, SPIE, Bellingham, Washington.
Andrews, L. C., Phillips, R. L., 2005, Laser Beam Propagation through Random Media, SPIE, Bellingham, Washington.
Arpalı, S. A., Baykal, Y., 2009, ‚Bit Error Rates for Focused General-Type Beams‛, in Progress in Electromagnetics Research Symposium, Moscow, Russia, Vol. 5, No. 7, pp. 633-636.
Arpalı, S. A., Eyyuboğlu, H. T., Baykal, Y., 2008, ‚Bit Error Rates for General Beams‛, Applied Optics, Vol. 47, No. 32, pp. 5971-5975.
Ata, Y., Baykal, Y., 2014, ‚Scintillations Of Optical Plane And Spherical Waves In Underwater Turbulence‛, J. Opt. Soc. Am. A, Vol. 31, No. 7, pp. 1552-1556.
Baykal, Y., 2015, ‚Intensity Fluctuations of Multimode Laser Beams in Underwater Medium‛, J. Opt. Soc. Am. A, Vol.32, No. 4, pp. 593-598.
Baykal, Y., 2016, ‚Fourth-order Mutual Coherence Function in oceanic Turbulence‛, Applied Optics, Vol. 55, No. 11, pp. 2976-2979.
Cheng, M., Guo, L., Li, J., Huang, Q., Cheng, Q., Zhang, D., 2016, ‚Propagation of An Optical Vortex Carried by a Partially Coherent Laguerre-Gaussian Beam in Turbulent Ocean‛, Applied Optics, Vol. 55, No. 17, pp. 4642-4648.
Gerçekcioğlu, H., 2014, ‚Bit Error Focused Gaussian Beams in Weak Oceanic Turbulence‛, J. Opt. Soc. Am. A, Vol. 31, No. 9, 1963-1968.
Gerçekcioglu, H., Baykal, Y., 2011, ‘‘Annular Beam Scintillations in Non-Kolmogorov Weak Turbulence‛, Applied Physics B - Lasers and Optics, Vol. 106, No. 4, pp. 933-937.
Gerçekcioglu, H., Baykal, Y., 2013, ‚BER of Annular and Flat-topped Beams in Strong Turbulence‛, Optics Communication, Vol. 298-299, pp. 18-21.
Gerçekcioglu, H., Baykal, Y., 2013, ‚BER of Annular and Flat-topped Beams in non-Kolmogorov Weak Turbulence‛, Optics Communications, Vol. 286, pp. 30-33.
Gerçekcioglu, H., and Baykal, Y., Nakiboğlu, C., 2010, ‚Annular Beam Scintillations in Strong Turbulence‛, J. Opt. Soc. Am. A, Vol. 27, No. 8, pp. 1834-1839.
Gerçekcioglu, H., Baykal, Y., Eyyuboğlu, H. T., 2010, ‚BER of Annular Beams in Strong Turbulence‛, Applications of Lasers for Sensing and Free Space Communications (LS&C) Topical Meeting, OSA / ASSP/LACSEA/LS&C, LSTuA4, 3 pp.
Gökçe, M. C., Baykal, Y., 2016, ‚Scintillation Analysis of Multiple-input Single-output Underwater Optical Links‛, Applied Optics, Vol. 55, No. 22, pp. 6130-6136.
Ishimaru, A., 1978, Wave Propagation and Scattering In Random Media, Vol.2, Academic Press, New York.
Korotkova, O., Farwell, N., Shchepakina, E., 2012, ‚Light Scintillation in Oceanic Turbulence‛, Waves Random Complex, Vol. 22, No. 2, pp. 260-266.
Kumar, P. V., Praneeth, S. S. K., and Narender, R. B., 2011, ‚Analysis of Optical Wireless Communication for Underwater Wireless Communication‛, International Journal of Scientific & Engineering Research, Vol. 2, No. 6, pp.194-202.
Lu, W., Liu, L., Sun, J., 2006, ‚Influence of Temperature and Salinity Fluctuations on Propagation Behaviour of Partially Coherent Beams in Oceanic Turbulence‛, Journal of Optics A, Vol. 8, pp. 1052–1058.
Namazi, N., Burris, R. J., Gilbreath, G. C., 2007, ‚Analytical Approach to The Calculation of Probability of Bit Error and Optimum Thresholds in Free-Space Optical Communication‛, Optical Engineering, Vol. 46, 025007-1-025007-7.
Nikishov, V. V., and Nikishov, V. I., 2000, ‚Spectrum of Turbulent Fluctuation of Sea-Water Refractive Index‛, International Journal of Fluid Mechanics Research, Vol. 27, pp.82-98.
Peng, X., Liu, L., Cai, Y., Baykal,Y., 2017, ‚Statistical Properties of a Radially Polarized Twisted Gaussian Schell-model Beam in an Underwater Turbulent Medium‛, J. Opt. Soc. Am. A, Vol. 34, No. 1, pp. 133-139.
Sandalidis, H. G., Tsiftsis, T. A., Karagiannidis, G. K., Uysal, M., 2008, ‚BER Performance of FSO Links Over Strong Atmospheric Turbulence Channels with Pointing Errors‛, IEEE Communications Letters, Vol. 12, No. 1, pp. 44-46.
Tatarski,V. I., 1961, Wave Propagation in a Turbulent Medium, McGraw-Hill, New York.
Tyson, R. K., Canning, D. E., Tharp, J. S., 2005, ‚Measurement of The Bit-error Rate of an Adaptive Optics, Free-space Laser Communications System, part 1: Tip-tilt Configuration, Diagnostics, and Closed-Loop Results‛, Optical Engineering, Vol. 44, 096002-1-096002-6.
Vetelino, F. S., Young,C., Andrews,L., 2007, ‚Fade Statistics and Aperture Averaging for Gaussian Beam Waves in Moderate-To Strong Turbulence‛, Applied Optics, Vol. 46, No. 18, pp. 3780–3789.
Yi, X., Li, Z., and Liu, Z., 2015, ‚Underwater Optical Communication Performance for laser Beam Propagation Through weak Oceanic Turbulence‛, Applied Optics, Vol. 54, No. 6, pp. 1273- 1278.
Yousefi, M., Golmohammady, S., Mashal, A., Kashani, F. D., 2015, ‚Analyzing the Propagation Behavior of Scintillation Index and Bit Error Rate of a partially Coherent Flat-Topped Laser Beam in Oceanic Turbulence,‛ J. Opt. Soc. Am. A, Vol. 32, No. 11, pp. 1982-1992.