Frequency comb interband cascade laser stabilization by time-delayed optical self-injection

Interband cascade laser (ICL) optical frequency combs are promising midwave infrared sources for dual comb spectroscopy probing the strong fundamental absorption lines of numerous chemical and biological agents. In this work, a 4-mm-long ICL frequency comb emitting at 3.3 μm was operated by single-cavity optical self-injection. The experiments employing a free-space optical self-injection length of 1.1m with fine-delay control demonstrated a tuning range of 119MHz around the free-running intermode beat frequency of 9.58 GHz. For resonant fine-delay the line width of the intermode beat frequency was reduced to 390 kHz, what is an improvement by a factor of 40 in comparison to the solitary laser line width.