All Fiber Couplers (Fiber Ports) and Collimators sorted by which fiber type they will be used with: There are Couplers for coupling into single-mode or polarization-maintaining fibers with high efficiency and pointing stability and Fiber Collimators that produce a collimated (low divergence), Gaussian beam exiting a single-mode (or polarization-maintaining fiber). Different series of Fiber Couplers and Fiber Collimators are designed to be used with multi-mode fiber cables.