BER OF ANNULAR BEAMS IN WEAK OCEANIC TURBULENCE

Abstract

Based on Rytov method, on-axis scintillation index of laser communication link in a weak

oceanic medium is formulated for collimated annular beam. Employing these obtained scintillation

values, 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 size

s1  , varying

annular beam thickness, propagation distance L , source size s  , the rate of dissipation of the mean

squared temperature T  , non-dimensional parameter representing the relative strength of temperature

and salinity fluctuation w. <BER> versus the source size and the average signal to noise <SNR> found

for the collimated annular beams are exhibited for various rate of dissipation of turbulent kinetic energy

per unit mass of fluid  and source sizes s  . At the stated link lengths, as secondary source size of

annular beam equals to zero, that is, for Gaussian beam, <BER> will offer more advantages.

Keywords

• Oceanic turbulence
• Ocean optics
• Optical communication
• Scintillation

Halkasal Hüzmenin Zayıf Okyanussal Türbülansta Bit Hata Oranı

Öz

Rytov yöntemine dayalı olarak zayıf bir okyanussal ortamdaki lazer iletişim bağlantısının eksen

üzerine ıpıldama indeksi, paralelleştirilmiş halka hüzmesi için formüle edilmiştir. Elde edilen bu

değerler kullanılarak, ortalama bit hata oranı (<BER>), log-normal dağılımlı olarak değerlendirilmiştir.

Paralelleştirilmiş halkalı hüzmelerin ıpldama indeksleri; sabit birincil kaynak boyutu

s1  , değişen

dairesel hüzme kalınlığı, yayılma mesafesi L , kaynak boyutu s  , ortalama karesel sıcaklığın dağılma

oranı T  , sıcaklık ve tuzluluk dalgalanmasının göreli kuvvetini temsil eden boyutsuz parametresiw

için 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 çeşitli

dağılım oranı için sergilenmektedir. Belirtilen iletişim bağlantısında, halkasal hüzmelerin ikincil kaynak

boyutu sıfıra eşit olduğunda, yani Gaussian hüzmesi olduğunda, <BER> daha fazla avantaj

sağlayacaktır.

Anahtar Kelimeler

• Okyanussal türbülans
• Okyanus optiği
• Optiksel haberleşme
• ıpıldama

Kaynakça

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