Achieving comb formation over the entire lasing range of quantum cascade lasers

作者：Yang Yang^*; Burghoff David; Reno John; Hu Qing

来源：Optics Letters, 2017, 42(19): 3888-3891.

DOI：10.1364/OL.42.003888

Frequency combs based on quantum cascade lasers (QCLs) are finding promising applications in high-speed broad-band spectroscopy in the terahertz regime, where many molecules have their "fingerprints." To form stable combs in QCLs, an effective control of group velocity dispersion plays a critical role. The dispersion of the QCL cavity has two main parts: a static part from the material and a dynamic part from the intersubband transitions. Unlike the gain, which is clamped to a fixed value above the lasing threshold, dispersion associated with the intersubband transitions changes with bias, even above the threshold, and this reduces the dynamic range of comb formation. Here, by incorporating tunability into the dispersion compensator, we demonstrate a QCL device exhibiting comb operation from I-th to I-max, which greatly expands the operation range of the frequency combs.

• 出版日期2017-10-1
• 单位MIT