| Because of the widely application of high power diode laser in materialprocessing, fiber laser pumping, laser remanufacturing and country security, theresearch of high brightness, high power laser source based on diode laser combinationbecame the research focus. Because of the poor beam quality and "smile" effect ofdiode laser stacks, it is difficult to increace the output power from small core fiber,which results in a low brightness. The fiber coupled module based on multiple singleemitter diode lasers can realize the high brightness with good beam quality, highreliability and long lifetime. Therefore the researching of single emitter diode laserscombination is a very significant subject. According to the demand of output power inmany applications, many kinds of modules with different fiber core and output powerwere designed and manufactured, the adjustment of fiber coupling and air-cooled heatwere discussed in this paper. The main contents and results of this paper are asfollows:1. A new structure of single emitter diode lasers combination was created, whichobtained the patent of invention. Many diode lasers light were space combined by theuse of multiple reflection prisms. Through adjusting the position of reflection prismsand diode lasers, the beam spot after combination was a nearly circular distribution, sothe focusing spot was circular, which matched the shape of fiber end. This structuresolved the problems of low filling ratio and low coupling efficiency in fiber coupling.2. Many kinds of modules with different fiber core and output power weredesigned and manufactured. First, the fast axis and slow axis of each diode laser werecollimated by micro-lens. The collimated beam of diode lasers was combined in fastaxis direction. Then the combined beam was polarization combined by PBS prism.Finally we utilized a suit of optical system designed by ourselves to expand and focusthe beam into a optical fiber. Which greatly increase the brightness of module of fibercoupled LDs. One of the modules could output15.22watts from a105μm multimode optical fiber. The numerical aperture of fiber was0.2. The brightness of moduleexceeded1.4MW/cm2-str. Another module could achieve162watts output powerfrom a300microns fiber core with a numerical aperture of0.22. Such high powermodules with single emitters combination were not reported before in homeland.3. The alignment error in single emitter diode lasers combination was analysisedby using the ray tracing method. Using the sequence model of optical design softwareto simulate the error of optical adjustment,the impact of beam propagation andcoupling efficiency was discussed. Which included the position error Δx, Δy, Δz,angle error βx, βy, βz of FAC and SAC, the position error ΔL in beam expandingsystem and the mismatch of a focused laser beam and optical fiber, which would havedirective function in the optical adjustment of single emitter diode lasers combination.4. A hundred-watt all-solid-state air-cooled, small engineering diode laser sourcewas designed. Combined with the principle of forced air cooling, through theoptimization of the size of radiator fan, the position of heat pipe and fan speed, ahundred-watt fiber coupling module air-cooled radiator was design and manufactured.Through the optimization of interface thermal resistance of optical fiber coupledmodule, the thermal resistance of whole module was less than0.15℃/W, which wasused in the air-cooled of160W fiber coupled module. Through the frequency red-shifttesting of fiber coupled module, which showed the reliable of radiator. So thehundred-watt all-solid-state air-cooled, miniaturization, engineering diode laser sourcewas achieved. A patent of invention based on this structure was applied.
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