Abstract: A method of inducing light losses at a parasitic wavelength in a fiber laser system includes providing a wavelength discriminator (WD) spaced from and between feeding and process fibers or from the end output of the feeding fiber so as to induce losses of light at parasitic wavelength. The device implementing the disclosed method is configured with a laser source, the delivery fiber and WD spaced at a distance between the surface to be treated and the end of the delivery fiber, wherein the WD receives the parasitic light over free space and is configured as a dichroic filter inducing losses to the light at the parasitic wavelength.

Abstract: A fiber laser is configured with a double clad fiber with a core doped with ions of Erbium (Er+3) and Ytterbium (Yb+3). At least two spaced apart high and low reflection mirrors flank the core and define a resonant cavity therebetween. The fiber laser further includes a pump laser outputting light in a 1.02-1.06 ?m wavelength range which is coupled into the Yb:Er doped double clad fiber. A fiber amplifier includes a double clad fiber with a core doped with ions of Erbium (Er+3) and Ytterbium (Yb+3), and a pump laser generating radiation at a pump wavelength in a 1.02-1.06 wavelength range, a pump laser outputting light in a 1.02-1.06 ?m wavelength range coupled into the Yb:Er doped double clad fiber. The disclosed fiber laser and fiber amplifier each have a significantly higher lasing threshold in the 1 ?m wavelength range than the threshold of the known schematics operating at a 9xx nm pump wavelength.

Abstract: A method of inducing light losses at a parasitic wavelength in a fiber laser system includes providing a wavelength discriminator (WD) spaced from and between feeding and process fibers or from the end output of the feeding fiber so as to induce losses of light at parasitic wavelength. The device implementing the disclosed method is configured with a laser source, the delivery fiber and WD spaced at a distance between the surface to be treated and the end of the delivery fiber, wherein the WD receives the parasitic light over free space and is configured as a dichroic filter inducing losses to the light at the parasitic wavelength.

Abstract: A method of inducing light losses at a parasitic wavelength in a fiber laser system includes providing a wavelength discriminator (WD) spaced from and between feeding and process fibers or from the end output of the feeding fiber so as to induce losses of light at parasitic wavelength. The device implementing the disclosed method is configured with a laser source, the delivery fiber and WD spaced at a distance between the surface to be treated and the end of the delivery fiber, wherein the WD receives the parasitic light over free space and is configured as a dichroic filter inducing losses to the light at the parasitic wavelength.

Abstract: A high power fiber laser system is configured with a pump cascade and a laser cascade. The pump cascade includes a fiber amplifier provided with a MM core which is doped with ions of rare-earth element including either Er or Yb/Er. The MM core of fiber amplifier is configured with a double bottleneck-shaped cross section. The laser cascade has a fiber laser configured with a core which is doped with Tm ions. The pump light generated by the amplifier is coupled into the upstream end of the Tm laser.

Abstract: A multimode (“MM”) fiber oscillator is configured with MM active fiber doped with light emitters, a pair of MM passive fibers spliced to respective opposite ends of the MM active fiber, and a plurality of MM fiber Bragg gratings (“FBG”) written in respective cores of the MM passive fibers to provide a resonant cavity. The passive and active fibers are configured with respective cores which are dimensioned with respective diameters matching one another and substantially identical numerical apertures.

Abstract: A high power fiber laser system is configured with a pump cascade and a laser cascade. The pump cascade includes a fiber amplifier provided with a MM core which is doped with ions of rare-earth element including either Er or Yb/Er. The MM core of fiber amplifier is configured with a double bottleneck-shaped cross section. The laser cascade has a fiber laser configured with a core which is doped with Tm ions. The pump light generated by the amplifier is coupled into the upstream end of the Tm laser.

Abstract: A multimode (“MM”) fiber oscillator is configured with MM active fiber doped with light emitters, a pair of MM passive fibers spliced to respective opposite ends of the MM active fiber, and a plurality of MM fiber Bragg gratings (“FBG”) written in respective cores of the MM passive fibers to provide a resonant cavity. The passive and active fibers are configured with respective cores which are dimensioned with respective diameters matching one another and substantially identical numerical apertures.