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Abstract
This work is a theoretical study in the Course of improving the performance of the optical fibers. The material, waveguide, and total dispersion have been investigated for both fiber profiles: step index and graded index fibers. The wavelength-dependent (Sellmeier equation) on temperature is used to calculate the material dispersion for three types of fibers, fused silica, aluminosilicate, and vycor glass.
The dispersion compensation is studied by using dispersion compensating fiber technique.
The length of the dispersion compensating fiber is calculated for both fiber profiles. We have studied these lengths under the effects of core radius, relative refl-active index difference, and temperature. Germania doped fibers with different doping ratios (x) are also used to compensate the chromatic dispersion in single mode fibers (SMFs).
The core refl-active index Sellmeier equation as a function of the doping ratio (x) is used to obtain the value of dispersion. The calculated lengths of doped fibers are obtained with and without temperature effect. The dispersion of the higher order modes near cutoff is also described. Higher order modes in optical fibers exhibit large and negative chromatic dispersion when operated near cutoff. The LPo2, and LPn modes represent larger negative dispersion than other modes. Hence, these modes can be used as a dispersion compensator to give short lengths of dispersion compensating fibers (DCFs). The DCF length is calculated in the wavelength band 1530 - 1570 nm. The dispersion of the DCF and its length are studied for the first time at different values of the core radius, relative refractive index, and temperature. Furthermore, the dispersion and relative dispersion slopes are obtained and matched for both (DCFs) and (SMFs).