Articles you may be interested inNarrow versus broad asymmetric waveguides for single-mode high-power laser diodes

High power tapered lasers are designed and fabricated. A one-dimensional photonic crystal structure in the vertical direction is adopted to narrow the far field divergence. The thickness of the defect layer and the photonic crystal layers are optimized by analyzing the optical field theoretically. For tapered lasers, the continuous-wave power is 7.3 W and the pulsed power is 17 W. A maximum wall-plug efficiency of 46% under continuous-wave operation and 49.3% in pulsed mode are obtained. The beam divergences are around 11°and 6°for the vertical and lateral directions, respectively. High beam qualities are also obtained with a vertical M 2 value of 1.78 and a lateral M 2 value of 1.62. As the current increases, the lateral M 2 value increases gradually while the vertical M 2 value remains around 2.

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High-power high-brightness super large optical cavity laser diodes with an optimized epitaxial structure are investigated at the wavelength of 980 nm range. The thicknesses of P- and N-waveguides are prudently chosen based on a systematic consideration about mode characteristics and vertical far-field divergences. Broad area laser diodes show a high internal quantum efficiency of 98% and a low internal optical loss of 0.58 cm. The ridge-waveguide laser with 7 μm ridge and 3 mm cavity yields 1.9 W single spatial mode output with far-field divergence angles of 6.8° in lateral and 11.5° in vertical at full width at half maximum under 2 A CW operating current. The corresponding M values are 1.77 and 1.47 for lateral and vertical, respectively, and the corresponding brightness is 76.8 MW‧cm‧sr. The far-field divergence angles with 95% power content are in the range of 24.7° to 26.1° across the whole measured range.