Abstract
Optical frequency combs based on semiconductor lasers are a promising technology for monolithic integration of dual-comb spectrometers. However, the stabilization of offset frequency fceo remains a challenging feat due the lack of octave-spanning spectra. In a dual-comb configuration, the uncorrelated jitter of the offset frequencies leads to a non-periodic signal resulting in broadened beatnotes with a limited signal-to-noise ratio (SNR). Hence, expensive data acquisition schemes and complex signal processing are currently required. Here, we show that the offset frequencies of two frequency combs can be synchronized by optical injection locking, which allows full phase-stabilization when combined with electrical injection locking of both repetition frequencies f rep. A single comb line isolated via an optical Vernier filter serves as Master oscillator for injection locking. The resulting dual-comb signal is periodic and stable over thousands of periods. This enables coherent averaging using analog electronics, which increases the SNR and reduces the data size by one and three orders of magnitude, respectively. The presented method will enable fully phase-stabilized dual-comb spectrometers by leveraging on integrated optical filters and provides access for comparing and stabilizing f ceo to narrow-linewidth optical references. Show more
Publication status
publishedExternal links
Journal / series
Optics ExpressVolume
Pages / Article No.
Publisher
OpticaOrganisational unit
03759 - Faist, Jérôme / Faist, Jérôme
02205 - FIRST-Lab / FIRST Center for Micro- and Nanoscience
Funding
820419 - Quantum simulation and entanglement engineering in quantum cascade laser frequency combs (EC)
176584 - High-resolution QCL frequency comb spectrometer for the detection of trace gases and their isotopes (SNF)
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