Method of aligning optical fibers to a multi-port optical assembly

Abstract

A method of assembling an optical device for coupling optical fibers to a corresponding number of input/output ports of a stack of optical elements includes utilizing at least one controllable multi-state optical element to selectively switch the optical coupling among the ports. The controllable multi-state element is one element within a stack of polarization-manipulating elements having a configuration that allows the condition of the multi-state element or elements to dictate the optical coupling among the ports. In the preferred embodiment, the multi-state element is a Faraday rotator. The method may be used in either or both of a quality control application or a fiber-to-port alignment application. In the quality control operation, the stack of polarization-manipulating elements is tested to verify proper operation with respect to separating and selectively recombining polarization components of input beams. In the fiber-to-port alignment application, the fibers on the same side of the stack are first fixed in a parallel relationship with a known center-to-center distance that is equal to the center-to-center distance between corresponding ports of the stack. By optically aligning one of the fibers on the forward side of the stack with the fibers on the rearward side of the stack, at least one other fiber is automatically brought into registration with its corresponding port.