An arrangement that prevents carbonization of cladding, coating, or buffer layers of a surgical laser fiber due to thermal radiation reflected back into the fiber from, or emitted by, a target of the laser, includes a thermal radiation blocking, absorbing or diverting structure. The thermal radiation blocking, absorbing or diverting structure surrounds an end portion of the fiber that has been stripped of one or more coating and/or buffer layers, and may be made of a heat resistant material such as PTFE or polyimide to block heat from reaching the coating or buffer layers, an optical ferrule such as fused silica to guide the heat away from the fiber coating or buffer layers, or a high refraction index material such as UV adhesive.