High-precision Coaxial Fiber Collimator is a core optical component in high-end fields such as telemetry, optical communication, and precision detection. Its manufacturing process has strict requirements for material. Fiber couplers are also used for fiber-to-fiber coupling: Light from the first fiber is collimated with a fiber collimator and then focused into the second fiber by another collimator. Another application is the combination with a back-reflecting mirror and some additional optical element. They can also be used in reverse to focus light into a fiber. It typically consists of: Optical fiber section – single-mode fiber (SMF) is most common, but polarization-maintaining (PMF) or multimode fiber (MMF) can also be used.