Due to many factors, the current optical power of single-mode fiber lasers is limited to about 1 kW. These factors limit the power of optical fibers: Pharma Intermediate,Crystals Black Balls Iodine,White Crystal Cas No 57-83-0,Heterocyclic Compound Cas 55-22-1 Jiangsu Kaihuida New Material Technology Co., Ltd , https://www.khdchemical.com
1) Optical nonlinear effects including stimulated Brillouin scattering, stimulated Raman scattering and self-phase modulation;
2) Amplify spontaneous emission, which competes with the lasing wavelength for storage energy, limiting the maximum population inversion and the final emission energy;
3) The thermal rupture limit of the optical fiber is approximately 100 Wcm-1. Without exceeding the thermal rupture limit, if a 10 m long fiber consumes 15 Wm-1 of energy, a 1 kW fiber laser will consume <15% of the pump's absorbed energy, or 150 W per kilowatt;
4) If the maximum power is greater than 1 Mw at l060m, the pulse damage threshold in the 10μm core-doped erbium-doped fiber is greater than 60GWcm-2, and the continuous and surface damage threshold is approximately 1 Wcm-2. When the pulse length is less than 100ns, the autofocus threshold is about 4Mw and must be considered.
Increasing the mode field diameter, increasing the gain of the fundamental mode, inserting a spatial filter, increasing the loss of high-order modes, reducing the length of the optical fiber, and using a photonic crystal or a porous optical fiber can increase the maximum output power of the optical fiber and make the single optical fiber power reach 2 kW. However, the most efficient way to obtain high-power laser light is to use multiple fiber bundles to combine the output. IPG Corporation bundled multiple 250-400W mode fibers to obtain a high-power fiber laser system with an output of 10kW. Simple fiber bundles can of course achieve high power output, but the output beam is multi-mode and does not work well in some applications.