DISPERSION IN DIFFERENT SINGLE MODE OPTICAL FIBER MATERIALS AT DIFFERENT TEMPERATURES

Salim Raheem, Aqeel

	DISPERSION IN DIFFERENT SINGLE MODE OPTICAL FIBER MATERIALS AT DIFFERENT TEMPERATURES
Al-Qadisiyah Journal for Engineering Sciences
Article 1, Volume 4, Issue 3, 2011, Pages 381-392 PDF (0 K)
Author
Aqeel Salim Raheem
Abstract
Optical fiber is a physical medium for optical communication system. It is offer high capacity, very wide band and high data rate. There are two main problems in this physical medium that are dispersion and power loss. The significant restriction in optical fiber system is the dispersion. The dispersion affects the performance of the system and bit error rate. There are two types of dispersion Intermodal and Intramodal. Intermodal occurs in multimode fiber only. Intramodal occur in all type of fiber. The total dispersion in single mode fiber is the sum of material and waveguide dispersion. In this paper the effect of temperature variations on fiber dispersion is investigated. The temperature variant is a vital factor which plays an effective role on activity of the communication system especially in environmental of Iraq and other Middle East country. The Sellemeier Coefficients equation is derived for fixed and discrete temperature values. A derivation for this equation to fit continues variation of temperature is done in this paper for optical fiber. Depend on formula of dispersion, Sellemeier Coefficients equation and relation of refractive index at any temperature derivation of propagation constant with normalized frequency for waveguide dispersion is done. The Temperature effect on total dispersion is modeled for most popular material used in fabrication optical fiber, silica (SiO2), aluminosilicate (Al2SiO5) and vycor glass (96.4%SiO2 ,3% B2O3, 0.5%Al2O3, 0.1% Miscellaneous Traces). Both single mode step index and graded index fibers are considered. The results investigated by using MATLAB and Maple programs. The refractive index temperature dependence for all three fiber types are fitted in to straight line. The material dispersion and zero material dispersion "λo" wavelengths have approximately linear temperature dependence for all three fiber types. For wide range of increasing temperature [-100◦C to 100◦C] SiO2 and vycor glass fiber has less effect than for Aluminosilicate. The temperature variation shows the step index fiber batter than graded index fiber. The SiO2 is the best one of three fiber types.
Keywords
Temperature effect on dispersion; total dispersion; zero dispersion wavelengths; chromatic dispersion; optical fiber; Sellmeier coefficients; intermodal dispersion; interamodal dispersion; Sellemeier Coefficients; refractive index

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