Design and analysis of intense light beam by microlens engraved optical fiber

We demonstrate the design and simulation of intense light beam (ILB) achieved by concave microlens engraved lenticular fibers. Both single and multiple microlenses of spherical and elliptical shapes have been incorporated just inside the fiber core. The ILBs have been designed using commercial OptiFDTD simulator. We investigate the average light intensity and beam profile at several locations including near field, far field-1, and far field-2 after the end face of the optical fibers. For single microlens, elliptical-shaped microlens engraved optical fibers show higher light intensity compared to spherical-shaped microlens engraved fibers. Light intensity at the output of the single-microlens incorporated fibers shows increasing trend with the increase of the radius of curvature (R) of the microlenses, where the highest light intensity has been achieved for R = -17.65 mu m. For microlens array engraved lenticular fibers, 9-lens model having R = -8 mu m has shown the highest light intensity. Due to the interference of light coming out from neighbor microlenses, the diffraction pattern, i.e., beam profile at any particular plane, is different for different arrangements of the microlenses. The proposed lenticular fibers are expected to have a wide range of applications in micro-optical systems, especially in biomedical engineering. (C) 2019 Society of Photo-Optical Instrumentation Engineers (SPIE)