Modeling of high-peak-power vertically integrated VCSEL composite cavity with cascaded energy conversion

Chip-scale, kilowatt-scale peak-power short-pulse lasers are becoming increasingly important for applications in various fields. This study systematically explores the cascaded energy conversion and oscillation characteristics of vertically integrated composite cavity VCSEL with cascaded energy conversion, aiming to establish what we believe to be a novel route to achieve kilowatt-level high peak power short-pulse monolithically integrated lasers. In this paper, the stable oscillation conditions under different feedback coefficient and signal gain are investigated based on equivalent resonator theory. By deriving simultaneous coupled rate equations, the dynamics process on coupled oscillation in composite cavity are explored and the effective regime for achieving high peak power laser is uncovered. The effects of the reflectivity of the P-DBR R₂ and the absorption rate of the Nd:YAG A_Nd on the laser oscillation characteristics are further revealed analytically. Stable pulses with a highest peak power of 137.1 kW, a maximum pulse energy of 24.9 µJ, a pulse width of 123.7 ps are achieved in the vertically integrated composite cavity VCSEL within a 100 µm aperture. Additionally, by utilizing expanded 2D coherent VCSEL arrays with high beam quality, we obtained a maximum pulse energy up to 83.9 mJ with a slope efficiency of 0.54 W/A. Our work provides an avenue for steering on-chip integration and developing believed to be novel laser arrays capable of operating at high peak powers exceeding kilowatts, with potential applications in remote laser detection and ranging.