Frequency stability characterization of a quantum cascade laser frequency comb (pages 623–630)
Francesco Cappelli, Giulio Campo, Iacopo Galli, Giovanni Giusfredi, Saverio Bartalini, Davide Mazzotti, Pablo Cancio, Simone Borri, Borislav Hinkov, Jérôme Faist and Paolo De Natale
Version of Record online: 2 JUN 2016 | DOI: 10.1002/lpor.201600003
The attempt of frequency stabilizing a mid-infrared quantum cascade laser frequency comb (QCL-comb) against a metrological DFG comb through a single phase-locking chain is presented. A discussion on how the locking affects the physics of the system is carried out, finding that the current locking essentially acts on the effective refractive index to reduce the common noise, without perturbing the group refractive index and the mode spacing. Nonetheless, the single QCL-comb tooth linewidth is significantly reduced.