Fully Phase Stabilized Quantum Cascade Laser Frequency Comb

Abstract

Miniaturized frequency comb sources across hard-to-access spectral regions, i.e. mid-and far-infrared, have long been sought. Four-wave-mixing based Quantum Cascade Laser combs (QCL-combs) are ideal candidates, in this respect, due to the unique possibility to tailor their spectral emission by proper nanoscale design of the quantum wells. We demonstrate fullphase-stabilization of a QCL-comb against the primary frequency standard, proving independent and simultaneous control of the two comb degrees of freedom (modes spacing and frequency offset) at a metrological level. Each emitted mode exhibits a sub-Hz relative frequency stability, while a correlation analysis on the modal phases confirms the high degree of coherence in the device emission, over different power-cycles and over different days. The achievement of fully controlled, phase-stabilized QCL-comb emitters proves that this technology is mature for metrological-grade uses, as well as for an increasing number of scientific and technological applications.

Noise Measurement and Reduction in Mode-Locked Lasers: Fundamentals for Low-Noise Optical Frequency Combs

“…However, the limited pulse energy restrains feasible f ceo detection using traditional f-2f interferometry. Phase linking of these novel combs to fully stabilized mode-locked lasers is one feasible option to eliminate f ceo locking [166][167][168][169][170]. On the other side, on-chip devices also enable f ceo detection in EO-combs and microcombs [149,171].…”