Conventional round spot quadrant detector trackers are inherently non-linear. This non-linearity requires multiple iterations to converge onto perfect alignment with the object tracked. We created a system that generates a square spot. The convolution of a square spot with a circle, generated by the quadrant detector, allows this spot to achieve perfect alignment in one iteration. This invention is thus essential to any system that requires speed and accuracy. In this paper, we introduce the theory behind the square spot as well as the design of our linear optical quadrant detector tracking technology.