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To improve the output powers of Vertical Cavity Surface Emitting Lasers(VCSELs),a 977 nm VCSEL array with three In0.2Ga0.8As/GaAs0.92P0.08 strained Quantum Wells(QWs) was studied.The structures of the QWs were optimized and GaAsP with a larger band gap was chosen as the barrier material,and the band offsets of In0.2Ga0.8As/GaAs0.92P0.08 were calculated.The output powers of the devices which used In0.2Ga0.8As/GaAs0.92P0.08 and In0.2Ga0.8As/GaAs QWs were simulated theoretically and analyzed comparetively,respectively and the pulsed peak powers of two array devices were measured.Then,the performance of the array device was estimated by a functional method using a p-parameter determined by the turn-on voltage,threshold current,and the differential resistance.Experimental results show that the 4×4 VCSEL array with In0.2Ga0.8As/GaAs0.92P0.08 QWs and an emitting area of 0.005 cm2 can achieve a pulsed peak power of 123 W when the injecting current is 110 A,and its power density and slope efficiency are 45.42 kW/cm2 and 1.11 W/A,respectively.This output power is 13 % larger than that of the array with In0.2Ga0.8As/GaAs QWs and the same emitting area.Furthermore,the values of p parameter are 15 and 13 under CW operation and pulsed operation,respectively,which indicates that the device has relatively good performance.In conclusion,the 4×4 VCSEL array with three In0.2Ga0.8As/GaAs0.92P0.08 strained QWs is able to achieve higher output powers.

For increasing the output powers without improving drive currents to high power Vertical Cavity Surface Emitting Lasers(VCSELs),a VCSEL in series structure was presented.First,the VCSEL chips were soldered on a AlN ceramic heat sink,then the chips were connected by a wire bonding in series.The output powers of four-chip devices in series,two-chip devices in series and a single device were measured under microsecond and nanosecond pulses,which are 775,416,217 mW and 18.9,9.8,5 W,respectively.Test results show that the output powers of the first two kinds of devices in series are about 4 times and twice that of the single device.Moreover,the Full Width at Half Maximum(FWHM) of multiple-chip devices in series is slightly wider than that of the single device,which can be improved by choosing good uniformity cascade chips.In conclusion,the VCSEL in series structure can increase the output power without improving the drive current.