InGaN/GaN DFB laser diodes at 434 nm with deeply etched sidewall gratings
InGaN/GaN DFB laser diodes at 434 nm with deeply etched sidewall gratings
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具有深蚀刻侧壁光栅的 434 nm InGaN/GaN DFB 激光二极管
DOI：
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发表时间：
2016
期刊：
影响因子：
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通讯作者：
A. Kelly
中科院分区：
文献类型：
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作者：
T. Slight;O. Odedina;W. Meredith;K. Docherty;A. Kelly
我们报告了在InGaN/GaN材料系统中的深蚀刻侧壁光栅DFB激光器，其在434 nm附近发射单个波长。GaN激光器在通信、显示器和存储领域有着广泛的应用。具有良好的边模抑制比（SMSR）的单波长器件的可用性将允许解决进一步的应用，例如用于激光冷却的源和用于太阳背景自由通信的夫琅和费线路操作。侧壁蚀刻光栅具有制造不需要过度生长的优点，并且已经在一系列其他材料系统和波长中得到证明。重要的是，对于GaN基器件，这种设计有可能使制造引起的对外延结构的损伤最小化。我们研究了两种激光器的设计，一种是80%占空比的第三阶光栅，另一种是39阶部分光栅。对二维波导截面进行了模拟，以找到最佳的光栅宽度。为了制造，使用电子束光刻和ICP蚀刻到500 nm的深度在单个步骤中图案化激光脊和光栅。沉积接触金属，并将样品变薄并切割成1 mm长的腔体。解理的第三阶激光器在脉冲状态下发射，SMSR为20 dB，峰值单模输出功率为40 mW。输出功率类似于并行处理的FP激光器。第39阶激光器在10 mW的输出功率下也表现出窄的光谱宽度。
We report on deeply etched sidewall grating DFB lasers in the InGaN/GaN material system emitting at a single wavelength around 434 nm. GaN lasers have a wide range of applications in communications, displays and storage. The availability of a single wavelength device with a good side mode suppression ratio (SMSR) would allow further applications to be addressed such as sources for laser cooling and Fraunhofer line operation for solar background free communications. Sidewall etched gratings have the advantage of fabrication with no need for overgrowth and have been demonstrated in a range of other material systems and wavelengths. Importantly for GaN based devices, this design has the potential to minimise fabrication induced damage to the epi structure. We investigated two laser designs, one with 80 % duty-cycle 3rd order gratings and another with 39th order partial gratings. Simulation of the 2D waveguide sections was carried out to find the optimal grating width. For fabrication, the laser ridge and gratings were patterned in a single step using electron beam lithography and ICP etched to a depth of 500 nm. Contact metal was deposited and the sample thinned and cleaved into 1 mm long cavities. The as-cleaved 3rd order lasers emit in the pulsed regime with a SMSR of 20 dB and a peak single-mode output power of 40 mW. The output power is similar to that of parallel processed FP lasers. The 39th order lasers also exhibit narrow spectral width at an output power of 10 mW.