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To improve the wire bonding and homogeneous injecting currents,this paper proposes a Vertical Cavity Surface-emitting Laser(VCSEL) array with a non-closed structure.In this structure,a non-closed groove is etched to form a mesa for simplifying the processing and reducing the damage of devices.The 850 nm VCSEL arrays(including 2×2,3×3 and 4×4 array devices) with the non-closed type top emission structures are tested and analyzed.Results show that the continuous output powers are up to 80,140 and 480 mW at room temperature,threshold currents are 0.15,0.25 and 0.4 A,and the far-field divergence angles in parallel and vertical directions are 9° and 9.6°,13.5°and 14.4°,15° and 14.4°,respectively.In the context of a pulse width of 50 μs and a pulse repetition rate of 100 Hz,the maximum output powers are 90,318 and 1 279 mW and the threshold currents are 0.2,0.5 and 0.7 A,respectively.The power curves of chips are tested before and after packaged.The result shows that the heat saturation current of the chip after packaged is much higher than that of the chip before packaged,which suggests that good packaging can improve the cooling efficiency and reduce the effect of internal heating on the device performance.

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.

High-brightness tapered laser diode at 850 nm was fabricated based on the AlGaInAs/A1GaAs chip with graded-index waveguide separate confinement hetero-structure.The tapered laser has better performance than the broad laser under the same condition.The lateral divergence angles of the tapered laser and the broad laser were 4° and 6° at the output power of 1 W,while the beam propagation factor M2 were 2.8 and 9.2,respectively.The slope efficiency of the tapered laser had a high value of 0.58 W/A and the conversion efficiency reached 30% in the output power 1.40 W under the injection current of 3 A.The facts indicated the tape-red laser would be an ideal choice for high brightness high power laser diodes.