Fiber collimators made by Schäfter+Kirchhoff are designed for singlemode fibers with FC connectors (optionally type ST, DIN AVIO and F-SMA). Fibers with 8°-polish (FC-APC, for avoidance of back-reflection into the optical path) are combined using fiber collimators 60FC-4-… and 60FC-T-4-… with an inclined coupling axis. This provides a centered and concentrically symmetric laser beam as effectively as a 0°-polished fiber attached to a fiber collimator with a coaxial coupling axis.
The fiber collimators have an axial limit stop for the fiber ferrule, which is locked using a grub screw to ensure a constant focal position and highly reproducible assembly. The eccentric key is used to focus the fiber collimator and the desired position is locked using two radially arranged clamping screws.