Fluid cooled optical fibers are disclosed. An exemplary fiber comprises a fiber body including a distal end, an inner cap surrounding said distal end, an outer cap surrounding said inner cap, and a tube attached to said outer cap. The tube and outer cap may define a first flow channel, the outer and inner caps may define a second flow channel, and the outer cap may including one or openings for placing the first flow channel in communication with the second flow channel. Associated systems also are disclosed.