808 nm大功率无铝有源区非对称波导结构激光器

采用分别限制非对称波导结构,将光场从对称分布变为非对称分布,降低了载流子光吸收损耗,并允许p型区具有更高的掺杂水平,从而使器件电阻降低.对GaAsP/GaInP张应变单量子阱(SQW)非对称波导结构激光器的光场特性进行了理论分析,设计了波导层厚度,并制作了波长为808 nm的无铝有源区大功率半导体激光器.器件综合特性测试结果为:腔长900μm器件的阈值电流密度典型值为400 A/cm2,内损耗低至1.0 cm-1;连续工作条件下,150μm条宽器件输出功率达到6 W,最大斜率效率为1.25 W/A.器件激射波长为807.5 nm,平行和垂直结的发散角分别为3.0°和34.8°.20~70℃范围内特征温度达到133 K.结果表明,分别限制非对称波导结构是降低内损耗,提高大功率半导体激光器特性的有效措施.

808 nm High-Power Lasers with Al-Free Active Region with Asymmetric Waveguide Structure

Shifting of the optical mode from symmetric distribution to asymmetric distribution by separate confinement asymmetric waveguide structure reduces optical absorption loss by carriers, and permits higher doping of the p side to reduce resistance. Based on the theoretical analysis for the optical field distribution characteristics of GaAsP/GaInP tensile-strained single quantum well (SQW) lasers with asymmetric waveguide, the thickness of waveguide layers was optimized, and a high-power semiconductor laser with Al-free active region was fabricated and studied experimentally. For a 900 μm cavity length device, the typical threshold current density is 400 A/cm2, and a low internal loss around 1.0 cm-1 is achieved. Under continuous wave (CW) operation condition, 150 μm aperture devices achieve a CW output power of 6 W, the maximum slope efficiency of the prepared devices is 1.25 W/A, and the lasing wavelength is 807.5 nm. Horizontal and vertical far-field divergence angles are 3.0° and 34.8°, respectively. The characteristic temperature of the laser in the range of 20～70 ℃ is estimated to be about 133 K. Separate confinement asymmetric waveguide structure is proven to be an impactful method for reducing optical loss and improving the characteristics of high power diode lasers.