In this work, a design for a mid-infrared quantum cascade laser frequency comb source that enhances the high frequency response and the comb characteristics of the device is presented. A state-of-the-art active region, grown on a heavily n-doped InP:Si substrate, was processed into a buried heterostructure with a microstrip-like line waveguide. As a result, the repetition rate frequency f_rep, around 11.09 GHz, can be locked to an injected narrow-linewidth radio frequency (RF) signal, over a range of more than 200 kHz with an injected power of −10 dBm, which outperforms normal buried heterostructure schemes by an order of magnitude. Moreover, under RF injection at powers higher than 20 dBm, the lasing spectrum is flattened and significantly broadened, from 24 ${\text{cm}}^{-1}$ to 65 ${\text{cm}}^{-1}$ in bandwidth, while at the same time, the coherence of the comb is maintained and verified.

中文翻译：

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具有微带状线波导几何形状的中红外量子级联激光器频率梳

在这项工作中，提出了一种中红外量子级联激光器频率梳状光源的设计，该设计可增强器件的高频响应和梳状特性。在重掺杂n的InP：Si衬底上生长的最新有源区通过微带状线波导加工成掩埋的异质结构。结果，大约11.09 GHz的重复频率频率f _rep可以锁定到注入的窄线宽射频（RF）信号，该信号在200 kHz以上的范围内，注入功率为-10 dBm，优于正常埋藏异质结构方案的数量级。此外，在功率高于20 dBm的RF注入下，激光光谱从24倍变平并明显变宽。${\text{厘米}}^{-\mathrm{1个}}$ 至65 ${\text{厘米}}^{-\mathrm{1个}}$ 在带宽上，同时保持并验证了梳的一致性。