دراسة خصائص انتقال لمتضمنات صوتي - ضوئي عالي السرعة والتردد == Study The Transmission Characteristic of Acousto - Optic Modulators for High Modulator Speed and High Frequency
Author name:
لبابة عبد الكریم الجنابي
Supervisor name:
سھى موسى خورشید الاوسي
General topic:
Physics
Specific topic:
Atomic Physics
Degree:
Master
University:
Al-Nahrain University - College Of Science - Physics Department
Language:
English
University location:
Baghdad
First pages:
26T1732 - p.pdf
Abstract:
Acousto optics is a science that studying the light and acoustic interaction for purposes of manufacturing modulators and sensors. The technology turned to the use of acousto optic to solve the problem of transforming the communication technology from the traditional one that used the radio signal in coaxial cable into the modern one that uses the laser light in the optical fibers. Also, this enables to overcome the problem of loss and attenuations that occur in the transmission lines using the traditional technology. More sophisticated methods are suggested to help communication researches; one of the most interesting acousto optic applications are the modulators. The modulators are manufactured for specific applications, such that the input energy power and light frequency are taken in to account. The modulator of this application can achieve high accuracy with some co - operation related to the suitability of used material.In the present research, a high speed and high frequency modulator are proposed based on the concept of acousto optic interaction. The occurrence of the interaction requires existence some experimental material arranged in uniform modulator template. The analysis enables to determine the requirements of the proposed modulator design. The newly proposed idea is the use of highly transparent material that absorbed the interference associated with diffraction. Four types of materials are used to test the proposed designed modulator; they are : LiNbO3, SiO2, TeO2, and Ge, the use of such materials offer rich considerable results especially when using different light frequencies to be input into the interaction system. The proposed modulator design is computerized implemented using Comsolsoftware with predefined characteristics are determined in the stage of the analysis and requirements. As a result, different results are obtained for different use of materials and characteristics.The results are examined using validation test, which includes some performance indications. These indications are achieved by two paths : the first is the measurements of operating parameters that obtained by Comsol directly, while the latter is related to computations of efficiency that achieved programming the theoretical relations using MatLab. Actually, the measurements in the first path are documented to ensure the acceptable performance of the proposed designed modulator, whereas the computations of the second path are recorded to ensure the high performance efficiency of the proposed modulator design. In general, the achieved results were matching the state of art given in most advanced literatures, which ensure the validation of the proposed design and correct paths of performance description.The results showed that the proposed modulator design performed the modulation test with an efficiency percent of about 95%, when using LiNbO3 material in the modulator head, and this efficiency is decreases lightly when using other materials. Besides, the employed measurements and computations are nominating the use of LiNbO3 material rather than others to be used in such types of modulators due to its suitable optical features.Frequent practice tests showed that the behavior of the modulator was acceptable and it is enjoying the ability to be improved. The encouraging results gave the opportunity to suggest some developments for future work in order to strength the modulation results.
