Actuator Stress and Operational Stability in HI MEMS‐VCSEL

ABSTRACT This study investigates the micromechanical mechanisms governing wavelength tuning stability in heterogeneously integrated MEMS vertical‐cavity surface‐emitting lasers (HI MEMS‐VCSELs) through dynamic stress distribution and modal perturbation analysis. A parametric model based on the circular arc cantilever central angle ( θ ) is established. Using COMSOL simulations, the coupling relationships among electrostatic driving force, frequency response, higher‐order parasitic modes, and stress topologies are systematically evaluated. The coefficient of variation and symmetry relative to mean absolute (SRMA) are introduced to quantify spatial stress dispersion and bending moment asymmetry. A parameter sensitivity perturbation analysis under a +3% stiffness fluctuation ( Δk/k 1 = +3%) confirms that the optimized center angle design ( θ = 40°) strikes an optimal balance between stress symmetry (SRMA = 34.50%) and dynamic performance, suppresses parasitic tilt modes by over 40 dB (down to −35.89 dB). Fabricated devices validated via free‐space Michelson interferometry and Hilbert phase demodulation demonstrate that the θ = 40° device maintains superior low‐frequency motion uniformity ( U m < 2.1%) down to a critical frequency of 0.5 Hz. A four‐factor signal decomposition framework ( I total ) and a forced harmonic oscillator fitting model comprehensively deconstruct the origins of non‐uniform oscillations and damping variations. This work establishes a multi‐dimensional micromechanical evaluation paradigm, offering robust theoretical and experimental guidelines for designing highly stable MEMS‐VCSELs for swept‐source imaging and precision sensing.