Dispersion compensated mid-infrared quantum cascade laser frequency comb with high power output

Abstract

Chromatic dispersion control plays an underlying role in optoelectronics and spectroscopy owing to its enhancement to nonlinear interactions by reducing the phase mismatching. This is particularly important to optical frequency combs based on quantum cascade lasers which require negligible dispersions for efficient mode locking of the dispersed modes into equally spaced comb modes. Here, we demonstrated a dispersion compensated mid-IR quantum cascade laser frequency comb with high power output at room temperature. A low-loss dispersive mirror has been engineered to compensate the device’s dispersion residue for frequency comb generation. Narrow intermode beating linewidths of 40 Hz in the comb-working currents were identified with a high power output of 460 mW and a broad spectral coverage of 80 cm-1. This dispersion compensation technique will enable fast spectroscopy and high-resolution metrology based on QCL combs with controlled dispersion and suppressed noise.

Coupled‐Waveguides for Dispersion Compensation in Semiconductor Lasers

“…The signal over noise characteristics of dual comb spectrometers heavily depend on the linewidth and stability of the comb devices. Recent experiments where Gires‐Tournois dielectric coatings were deposited on the back facet of QCL devices showed the essential role of dispersion compensation for the improvement of the combs bandwidth and operation stability . However, dispersion compensation by waveguide engineering is preferable in terms of its capability to correct for large amounts of dispersion, as well as its reliability and cost.…”

Kerr nonlinearity and group velocity dispersion of InGaAs/InP and GaAsSb/InP waveguides in the mid-infrared

“…[1][2][3][4] Direct frequency comb generation inside of mid-IR quantum cascade (QCLs) and interband cascade lasers (ICLs) has been demonstrated; [5][6][7][8] however, the bandwidth of these frequency combs is currently limited to ∼100 cm −1 by the difficulty of maintaining a flat gain profile and managing the group velocity dispersion in the laser waveguides. [5][6][7][8][9] In parallel, octavespanning Kerr frequency comb generation in passive micro-ring resonators [10][11][12][13] has been experimentally demonstrated in the nearinfrared spectral range (λ < 3 μm), and similar approaches are being explored in the 3-5 μm spectral range using SiN-and Si-based micro-ring resonators. 14,15 Additionally, on-chip supercontinuum generation in SiN, Si, and SiGe-based waveguides has been shown to be able to extend the spectral bandwidth of pulsed mid-IR sources to an optical octave or more.…”