Broadband supercontinuum light emitting device comprising at least the following: - a nonlinear optical fiber; - a pump system; - a cavity (R1, R2); and - an active medium (Fm), located inside said cavity, configured and arranged to, by means of a pumping provided by said pump system, generate and emit pulses of light towards said nonlinear optical fiber which excite the nonlinear effects thereof in order to generate and emit said supercontinuum light by an output end of the nonlinear optical fiber; wherein the device is characterized in that: - said nonlinear optical fiber is arranged inside said cavity; - said active medium comprises a portion of active fiber (Fm) with an output end connected to an input end of the nonlinear optical fiber; - the pump system comprises a pump diode connected to an input end of said portion of active fiber (Fm) to emit light towards that portion of active fiber (Fm); - said cavity and said active medium are configured so that the pulses of light generated and emitted by the active medium are chaotic pulses of light that excite the nonlinear effects of the nonlinear optical fiber to make the nonlinear optical fiber generate and emit supercontinuum light in the form of pulses of light distributed randomly over time; - an additional portion of optical fiber (Fn) connected to an input end of the portion of active fiber (Fm), in which at least one first element being a fiber Bragg grating of reflectivity higher than 0.9, and a free end of the additional portion of optical fiber (Fn) that ends at a non-right angle are provided; - at least one second element of reflectivity lower than 0.1 that is arranged at or near said output end of the nonlinear optical fiber; and - said cavity is defined between the first element and the second element. - a nonlinear optical fiber; - a pump system; - a cavity (R1, R2); and - an active medium (Fm), located inside said cavity, configured and arranged to, by means of a pumping provided by said pump system, generate and emit pulses of light towards said nonlinear optical fiber which excite the nonlinear effects thereof in order to generate and emit said supercontinuum light by an output end of the nonlinear optical fiber; - said nonlinear optical fiber is arranged inside said cavity; - said active medium comprises a portion of active fiber (Fm) with an output end connected to an input end of the nonlinear optical fiber; - the pump system comprises a pump diode connected to an input end of said portion of active fiber (Fm) to emit light towards that portion of active fiber (Fm); - said cavity and said active medium are configured so that the pulses of light generated and emitted by the active medium are chaotic pulses of light that excite the nonlinear effects of the nonlinear optical fiber to make the nonlinear optical fiber generate and emit supercontinuum light in the form of pulses of light distributed randomly over time; - an additional portion of optical fiber (Fn) connected to an input end of the portion of active fiber (Fm), in which at least one first element being a fiber Bragg grating of reflectivity higher than 0.9, and a free end of the additional portion of optical fiber (Fn) that ends at a non-right angle are provided; - at least one second element of reflectivity lower than 0.1 that is arranged at or near said output end of the nonlinear optical fiber; and - said cavity is defined between the first element and the second element.