Passive Mode-Locking of 3.25 μm GaSb-Based Cascade Diode Lasers
Passive Mode-Locking of 3.25 μm GaSb-Based Cascade Diode Lasers
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DOI：
10.1021/acsphotonics.8b01215
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发表时间：
2018-12-01
期刊：
影响因子：
7
通讯作者：
Kipshidze, Gela
中科院分区：
文献类型：
--
作者：
Feng, Tao;Shterengas, Leon;Kipshidze, Gela
被动锁模I型量子阱级联二极管激光器发射近3.25 μ m的设计，制造和表征。利用分离接触结构实现了类似于5.5 μ m宽的单空间模脊形波导的深刻蚀设计。外延侧向上安装的3 mm长的脊形激光器具有2.7mm长的增益和300 μ m长的吸收体部分，其在20 ℃下以大于12 mW的输出功率在连续波区中操作。具有反向偏置吸收体部分的器件在类似于13.2GHz的重复率下产生类似于10 ps的脉冲，平均功率超过1 mW。在锁模制度的激光发射光谱包括一个光滑的钟形的频率梳，覆盖约20 nm的范围内的全宽在半最大水平。二阶干涉自相关的研究表明，在脉冲的光谱啁啾很强。观察到具有180 kHz线宽的洛伦兹形状的模间拍音，对应于约110 fs/周期的脉冲到脉冲定时抖动。在自相关扫描中观察到小程度的锁相，即使没有施加到吸收体部分的反向偏置。在可变增益和吸收体部分偏置的射频频谱的映射显示在低吸收体偏置部分电压下在两个非线性锁模制度之间切换。
Passively mode-locked type-I quantum well cascade diode lasers emitting near 3.25 mu m were designed, fabricated, and characterized. The deep etched similar to 5.5-mu m-wide single spatial mode ridge waveguide design utilizing split-contact architecture was implemented. The epi-side-up mounted 3-mm-long ridge lasers with both 2.7-mm-long gain and 300-mu m-long absorber sections forward biased operated in the continuous wave regime with above 12 mW of output power at 20 degrees C. The devices with a reverse biased absorber section generated similar to 10 ps pulses at the repetition rate of similar to 13.2 GHz with average power exceeding 1 mW. The laser emission spectrum in the mode-locked regime comprised a smooth bell-shape-like frequency comb covering about a 20 nm range at the full-width at half-maximum level. Second-order interferometric autocorrelation studies revealed a strong spectral chirp in the pulse. The intermodal beat note of the Lorentzian shape with a 180 kHz line width was observed, corresponding to pulse-to-pulse timing jitter of about 110 fs/cycle. The small degree of the phase-locking was observed in autocorrelation scans even without reverse bias applied to the absorber section. The mapping of the radio frequency spectrum over variable gain and absorber section biases showed switching between two bistable mode-locking regimes at low absorber bias section voltages.