We investigate theoretically and experimentally the dynamics of frequency comb formation triggered by mode-crossings in a normal group-velocity dispersion microresonator. We demonstrate that phase-matching conditions can predict the spectral features of the resulting combs.

We generate tunable offset-free gigahertz combs from 2.5 to 4.2 µm by supercontinuum generation in a Si3N4 waveguide followed by parametric amplification in PPLN waveguides with 35-dB gain. Noise and nonlinear dynamics are also investigated.

We generate offset-free gigahertz frequency combs tunable from 2.75 to 3.8 μm by using PPLN waveguides for 30-dB-amplification of a supercontinuum generated in a Si 3 N 4 waveguide by the same Yb:CALGO-laser that pumps the OPA process.

Compact laser frequency combs covering the midinfrared ``fingerprint'' spectral region are desirable light sources for high-sensitivity, high-resolution detection of target molecules. The authors leverage the nonlinear properties of chip-scale Si${}_{3}$N${}_{4}$ and periodically poled LiNbO${}_{3}$ waveguides to obtain a tunable, energy-efficient mid-IR frequency comb. Here the pulse energy needed for a given power per comb line is nearly two orders of magnitude lower than for conventional systems. These results are promising for applications in environmental, medical, and industrial diagnostics.

We present the first carrier-envelope-offset (CEO) frequency detection based on multi-octave-spanning supercontinuum generation in a CMOS-compatible Si3N4 waveguide. Strong CEO-beat-signals (>30 dB) of a gigahertz-Yb:CALGO-laser were obtained with only 36 pJ of coupled pulse energy.

We present the first self-referenced fCEO-stabilization based on Si3N4-waveguides, using only 36 pJ of coupled pulse energy. In addition, pump wavelength stabilization leads to record low noise performance of our 1-GHz diode-pumped solid-state laser.

We present the first direct carrier-envelope-offset (CEO) frequency detection of a modelocked laser based on supercontinuum generation (SCG) in a CMOS-compatible silicon nitride (Si(3)N(4)) waveguide. With a coherent supercontinuum spanning more than 1.5 octaves from visible to beyond telecommunication wavelengths, we achieve self-referencing of SESAM modelocked diode-pumped Yb:CALGO lasers using standard f-to-2f interferometry. We directly obtain without amplification strong CEO beat signals for both a 100-MHz and 1-GHz pulse repetition rate laser. High signal-to-noise ratios (SNR) of > 25 dB and even > 30 dB have been generated with only 30 pJ and 36 pJ of coupled pulse energy from the megahertz and gigahertz laser respectively. We compare these results to self-referencing using a commercial photonic crystal fiber and find that the required peak power for CEO beat detection with a comparable SNR is lowered by more than an order of magnitude when using a Si(3)N(4) waveguide.

We investigate experimentally and theoretically the role of higher-order-dispersion on the bandwidth of microresonator-based parametric frequency combs. Our results demonstrate that fourth-order dispersion plays a critical role in determining the spectral bandwidth.