Focusable Collimators consist of two separate components: a fiber optic collimator and a fiber optic refocusing assembly. The fiber optic collimator utilizes a PCX lens positioned at the focal length from the optical fiber tip. These collimators are available with FC or SMA threads, and easily couple to standard 0.22 NA fiber optic cables. Focusable Collimators expand the beam and decrease the divergence by the ratio of the fiber core diameter to the collimator aperture. Fiber optic refocusing assemblies mount directly to the fiber optic collimator and allow for optimal focus at a given distance.