808 nm high brightness module of fiber coupled diode laser

As 808 nm single emitter diode lasers have low output powers, they are limited to pump neodymium-doped double-cladding fiber lasers in end pumping. In order to enhance the pumping efficiency of the fiber laser by using single emitters, a fiber coupled module with several single emitter diode lasers was developed. First, the fast axis and slow axis of each diode laser were collimated by a micro-lens. Then, the output beams of diode lasers were combined with reflecting prisms. Finally, a suit of optical system designed by ourselves was utilized to expand and focus the beam into a optical fiber. Experiments show that this approach can greatly increase the brightness of the module with fiber coupled LDs. Four LDs with continuou output power of 5 W are coupled in a 105 μm multimode optical fiber with a core diameter of 105 μm and a numerical aperture of 0.2 when the working current is 5.8 A, it can offer the fiber output power of 15.22 W, coupling efficiency of 74% and the brightness over 1.4 MW/cm ²·sr.