GRIN rod lenses for optical fiber communication systems

Radially graded - refractive index (GRIN) rod lenses have a number of advantages over conventional lenses in manipulating and processing the optical signals in optical fiber communication systems(l). In order to have a device using GRIN rod lenses, design requirements are varied in nature. A system containing one or more than one radial grin lenses or a combination of radial and axial GRIN elements is designed. The next step is to develop the required GRIN elements with desired material properties. Finally, the system is optimised as a compromise between the ideal and real available GRIN elements. Ion exchange technique is the most widely used method to develop GRIN profile in glass due to its simple instrumentation and ease of control. We have developed a novel method to predict the GRIN profile for a given set of experimental conditions (2). This method helps us in developing different types of GRIN profiles in the glass rods with minimum number of experimentation. After the glass rods have gone through the process of ion exchange, refractive index profile are measured in a set - up developed by us (3,4). In this paper, we present the development of radial GRIN rod lenses with a diameter of 1 to 2 nun. These GRIN rod lenses can be used for coupling of laser light source to the optical fiber