Sharif Digital Repository

Intensity profiles for the single and fiber-to-fiber designs are described.Profiles for different arrangements using the red light LED and LED laser are compared. The near field output distribution bandwidths are compared and there is a close relation between the bandwidth and the source light, fiber size, and the fiber gap separation  

In this study the optical beam transfer and imaging in an optical fiber coupling is discussed. In coupling two fibers, some measurements from intensity perspective are performed and intensity profile is investigated. A theoretical model for the power transmission in fiber coupling is developed and theoretical function is compared with the experimental results. The amount of light delivered to the receiving fiber depends on the acceptance angle of the receiving fiber and the core cross sections of both fibers. Intensity profile function obtained theoretically agrees well with the measured results. The intensity variation as a function of the air gap variation is investigated in this article.... 

Experimental and theoretical results of a two-stage beam shaping system based on a flexible plastic fiber-bundle and a prism duct are described in this study. An imaging technique is used to investigate the divergence effect on the output beam images and intensity profiles. Photograph pictures of the output beam at different axial distances are taken by a digital camera and the image data is converted into a response curve and presented in this study. According to the experimental results, the propagation in the free space transforms a square beam with a hat-top intensity distribution into a rectangular beam with a conical intensity distribution. For theoretical investigations, using VOB... 

The lasing mechanism and temporal output profile of distributed feedback dye lasers is investigated, using a model based on induced polarization in the dye solution, where a more accurate behavior of the laser output is predicted. It is found that the temporal output profile of the laser is mostly determined by the concentration of dye solution and the lifetime of the upper laser level of dye molecules. To a large extent, the results of this work agree with experimental studies, even at high-level pump intensities where the self Q-switched model fails to be applied. Especially, the experimentally observed irregular intensity profile of laser output is explained. It is also shown that, when... 

Design and performance of a two-stage optical beam shaping system based on a plastic fiber-bundle prism-coupled waveguide is described in this study. Such systems offer practical means to modify and change the output beam shape at two stages and also provide quantitative information concerning the output beam intensity profile. It is possible to obtain reflection and image transmittance data by using a light source for the illumination and image analysis by a CCD/digital camera. Using the active lighting, the reflection data and image profiles for the output beam are obtained by a CCD camera and presented in this study. The photograph picture of the illuminating LED beam just at its output...