Performance evaluation of a silicon-rich nitride ring laser with a WSe₂ monolayer

A careful design approach is presented for an integrated nanophotonic laser cavity, consisting of a silicon-rich silicon nitride ring resonator and a transition metal dichalcogenide (TMD) monolayer (WSe₂) on-top as the optically pumped gain medium. The structure is analyzed and designed utilizing full-wave finite-element simulations and a comprehensive theoretical framework based on perturbation theory, temporal coupled-mode theory (CMT), and Maxwell-Bloch equations that rigorously capture both the temporal cavity (photonic) response and the carrier dynamics. The cavity is carefully designed following directives dictated by the utilized computational framework, ensuring a satisfying compromise between efficient pump absorption, low lasing threshold, and extended bandwidth up to 65 GHz. The dynamic response of the laser is in-depth examined by the CMT to estimate its direct modulation bandwidth in terms of system design parameters (cavity lifetime) and gain material properties (metastable carrier relaxation lifetime).