System and method for aligning optical fiber collimators

A method and apparatus of aligning a collimator assembly requiring only a single-axis adjustment and for which the collimator may be paired with any other similarly aligned collimator. A collimator typically includes a fiber grasped by a ferrule. Both the ferrule and a graded-index (GRIN) lens are eventually bonded to the inside of a glass tube with the fiber/lens distance fixed for optimum collimator performance. According to one method of practicing the invention, the tube/lens assembly is fixed, and the ferrule/fiber is slidably inserted into the tube. The position of the ferrule/fiber is adjusted within the tube while the size of the resultant beam is measured at a fixed distance from the output from the lens. If there are two such positions producing the optimum beam size, the position of less separation between the ferrule and fiber is chosen. The collimators aligned by the invention may be freely paired with each other (for example, within a sleeve or housing also containing an optical element located between the two collimators). An optimum beam size and optimum measuring distance may be established by an optical calculation or other optimization technique dictated for the intended use of the collimator.