Beam shape and intensity profile of a fiber-bundle prism-coupled waveguide

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 point shows a circular shape with a radius of about 5 mm. Picture of the fiber-bundle output beam is also taken, which shows a linear arrangement of circular spot lights almost similar in cross section. The output beam cross section at this stage is in rectangular shape with a dimension of 30 mm width and 3 mm height. In another study CCD images at prism exit face is obtained and image profile is investigated. The final output beam cross section at the second stage of beam shaping is a square with a dimension of about 5 by 5 mm. The transmitted output beam power is also measured at different stages. The conversion efficiency for the fiber bundle at first stage beam shaping is about 70% and for the overall system is about 15%. In another study the relative reflected light off the prism entering face is measured by using two fiber probes in the stripe cable, which shows the ability to monitor such reflections for selecting the prism duct with a lower reflection loss.