Optical fiber device for laser thermal ablation and thermal therapy

The device comprises at least a laser source (5); an optical fiber (1) with an optical radiation entrance end (1.2) and an optical radiation output end (1.1); and a coupling system (8) for coupling the laser source (5) and the optical fiber (1), adapted to inject an optical radiation emitted by the laser source (5) into the entrance end (1.2) of the optical fiber (1). The optical fiber (1) is a multi-mode optical fiber. The coupling system (8) is adapted to inject the optical radiation into the optical fiber (1) with such an inclination (a) as to reduce or eliminate the fundamental transmission mode and to promote the transmission according to at least one higher-order transmission mode The optical radiation at the output end (1.1) of the optical fiber (1) has a cone-shaped distribution (3) wherein the intensity is maximal on the peripheral volume of an emission cone and is minimal inside the emission cone.