Type-I QW cascade diode lasers for spectral region above 3 μm
Type-I QW cascade diode lasers for spectral region above 3 μm
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适用于 3 μm 以上光谱区域的 I 型 QW 级联二极管激光器
DOI：
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发表时间：
2016
期刊：
影响因子：
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通讯作者：
G. Belenky
中科院分区：
文献类型：
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作者：
L. Shterengas;T. Hosoda;M. Wang;T. Feng;G. Kipshidze;G. Belenky
利用 I 型量子阱增益部分的级联泵浦来提高在 3.1 至 3.3 μm 光谱范围内工作的 GaSb 基二极管激光器的输出功率和效率。实验表明，级联数量从两个（之前用于创纪录级联 3 μm 发射器）增加到三个，导致微分增益显着增强，并且 λ > 3 μm 激光器的阈值电流密度降低。 AlGaAsSb 分级部分的轻 p 掺杂不会引入额外的光学损耗，但有助于实现高效多级级联泵浦方案所需的空穴传输。相应的涂层三级器件具有约 100 μm 宽的孔径和 3 mm 长的腔体，在 17 °C 时在 3.18 μm 附近表现出 500 mW 的 CW 输出功率，与之前仅发射 200 mW 的最先进二极管激光器相比，增加了两倍多。具有量子阱的三级激光器设计用于在 3.25 μm 附近的甲烷吸收带中间发射，其输出功率水平达到创纪录的 350 mW 以上，比之前的非级联最先进二极管提高了近三倍。级联激光异质结构中不同量子阱的利用被证明可以产生可调谐激光光谱经常需要的宽增益激光器。应用两步蚀刻以同时最小化窄脊激光器中的内部光学损耗和横向电流扩散。
Cascade pumping of type-I quantum well gain sections was utilized to increase output power and efficiency of GaSb-based diode lasers operating in spectral region from 3.1 to 3.3 μm. The experiment showed that the increase of the number of cascades from two (previously used in record cascade 3 μm emitters) to three led to critical enhancement of the differential gain and reduction of the threshold current density of λ > 3 μm lasers. Light p-doping of the AlGaAsSb graded section did not introduce extra optical loss but aided hole transport as required for realization of the efficient multi-stage cascade pumping scheme. Corresponding coated three-stage devices with ~100-μm-wide aperture and 3-mm-long cavity demonstrated CW output power of 500 mW near 3.18 μm at 17 °C – more than twofold increase as compared to previous state-of-the-art diode lasers emitting only 200 mW. Three-stage lasers with quantum wells designed to emit in the middle of methane absorption band near 3.25 μm demonstrated record output power levels above 350 mW – nearly threefold improvement over previous non-cascade state-of-the-art diodes. Utilization of the different quantum wells in cascade laser heterostructure was demonstrated to yield wide gain lasers as often desired for tunable laser spectroscopy. Two step etching was applied in effort of simultaneous minimization of both internal optical loss and the lateral current spreading in narrow ridge lasers.