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العنوان
Performance Improvement of raman fiber amplifier /
المؤلف
Moustafa, Samer Elsayed Darwish.
هيئة الاعداد
باحث / سامر السيد درويش مصطفى
مشرف / مصطفى حسين علي
مشرف / أحمد شعبان سمره
مناقش / مصطفى حسين علي
الموضوع
Communication. Bidirectional Pump. Electronics. Noise Figure.
تاريخ النشر
2019.
عدد الصفحات
online resource (76 pages) :
اللغة
الإنجليزية
الدرجة
الدكتوراه
التخصص
الهندسة الكهربائية والالكترونية
تاريخ الإجازة
1/1/2019
مكان الإجازة
جامعة المنصورة - كلية الهندسة - الالكترونيات والاتصالات
الفهرس
Only 14 pages are availabe for public view

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from 98

Abstract

This dissertation is concerned with the study of characteristics of distributed Raman optical amplifier. Raman amplifier offers some advantages for fiber optical communication system with its large optical amplification bandwidth, where no special amplification medium is needed. In Raman amplification, a photon is scattered to create an optical phonon and a lower frequency photon; a Stokes photon. The optical gain is achieved at the Stokes frequency. The gain peak can be tuned by changing the pump wavelength. The distributed Raman amplification also provides high gain and low noise figure. One of the most crucial issues to consider in the distributed Raman amplifiers analysis is the effect of pump depletion due to the stimulated Raman scattering process because it strongly affects the amplifier performance. This thesis addresses the impact of pump depletion on the performance of bidirectional pump Raman amplifiers. It appears above threshold values of pump power of 330 mW, and fiber length of 135 km, respectively. We derived the mathematical expressions for threshold depletion length, threshold depletion pump power, and unity gain length in forward pump Raman amplifier. In the backward pump amplifier, an expression for the safe fiber length is derived such that the signal power can be amplified without losing its characteristics. Analytical expressions are also derived for the unity gain amplifier length in both forward and backward pumped amplifiers and for the maximum transmission length without a repeater for bidirectional pump amplifiers. In this case, the maximum unrepeatered transmission length obtained is 472 km at signal power of 0.1 µW and pump power of 0.5 W. Also, in this thesis, we provide a detailed analysis for the effect of pump depletion on the amplified spontaneous emission noise power, optical signal to noise ratio, and noise figure in forward pumped distributed Raman fiber amplifier. The optimum pump power for high optical signal to noise ratio, low noise figure and better gain is obtained as 256 mW at input signal power of 1 µW, fiber length of 120 km, fiber loss of 0.2 dB/km, and optical filter bandwidth of 0.5 nm. The obtained results are compared with the previously published ones showing a good agreement.