Mid-infrared frequency comb generation in passive III-V waveguides on InP platform

• Applicant: Professor Mikhail Belkin, Ph.D.
• Subject Area: Electronic Semiconductors, Components and Circuits, Integrated Systems, Sensor Technology, Theoretical Electrical Engineering
• Term: since 2021
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 463411319

The goal of the project is to investigate nearly-degenerate mid-infrared (mid-IR, wavelengths in the range 3-12 microns) four-wave mixing (FWM) in micro-resonators fabricated in the InP-compatible waveguiding platform and to demonstrate, for the first time, mid-IR frequency comb (FC) generation via parametric FWM in passive micro-resonators fabricated on InP substrates. The waveguide cores will be made of epitaxially-grown InGaAs or GaAsSb materials lattice-matched to InP with waveguide cladding layers made of InP. Our efforts in this project will focus on investigating FWM and demonstrating FCs in the wavelength range around 4.5-5.5 microns, where the waveguide losses are expected to be some of the lowest and where very-high-power single-mode QCLs are available to be used as optical pumps. We note, however, that intrinsic InGaAs, GaAsSb, and InP semiconductors have low loss and near-zero GVD across the entire 3-12 microns range. Thus, once demonstrated in 4.5-5.5 microns range, the FC generation in the InGaAs/GaAsSb/InP platform may be extended to the entire 3-12 microns spectral range. The experimental demonstration of mid-IR FC generation in micro-resonators on the InP platform will enable the development of electrically-pumped broadband frequency comb sources based on monolithic integration of continuous-wave InGaAs/AlInAs/InP quantum cascade laser (QCL) pumps with the passive micro-resonators. Monolithic QCL pump integration with the low-loss InP-based passive waveguides can follow the approach previously demonstrated by the Principle Investigator. The results of this project may lead to the realization of compact chip-scale broadband dual-comb mid-IR spectrometers that can displace bulky Fourier-transform infrared spectrometers for many applications and take sample spectra at very high speeds.

• DFG Programme: Research Grants