Numerical Study of Dual Mode Generation Using a Sampled-Grating High-Order Quantum-Dot Based Laterally-Coupled DFB Laser

We propose a fabrication-friendly dual-mode laser source based on a sampled surface-grating, quantum-dot (QD), third-order, and laterally-coupled distributed feedback (LC-DFB) laser composed of alternating grating and Fabry-Perot sections. The dynamic behavior of this device is investigated through numerical modelling, and mode spacing in the millimeter-wave domain (60 GHz) was achieved. We extended a time-domain travelling-wave algorithm, including Streifer's terms, to numerically study the dynamic behavior of the modified high-order LC-DFB lasers. We also incorporated an active QD region via a set of rate equations that considers both in homogeneous broadening because of spatial distribution of QD and homogeneous broadening because of the scattering or polarization dephasing rate. It was found that stable dual mode operation in the millimeter-wave range can be achieved with a dual-side-mode-suppression-ratio as high as ~ 50 dB.