The most challenging task in photonics assembly is the alignment and positioning of optical fibers and components. Submicron accuracy, fine resolution and high stability are required when coupling laser light with the core of an optical fiber. This delicate process is referred to as active alignment. Traditional active alignment involves coupling a light source, such as a laser, with one end of an optical fiber to determine the optimal position of the component at the other end of the fiber.
Manufacturers of lasers, amplifiers, connectors, filters, receivers, switches and other fiber optic components and modules are very concerned about the amount of signal loss that occurs across the component-to-component or component-to-fiber junction. Due to the extremely small size of optical fiber--8 or 9 microns for single-mode fiber cores, which is less than the width of a human hair--very high-resolution systems capable of producing nanometer-scale displacements are required to reduce losses across the optical junction.