Impact of Micromechanics on the Linewidth and Chirp Performance of MEMS-VCSELs

This paper studies the effects of microforces on micromachined active Fabry-Peacuterot laser cavities. A simple mechanical model is established to analyze the influence of these microforces on the microelectromechanical system (MEMS)-realization of the Bragg mirrors inside a microcavity. The presence of thermal noise of the MEMS structure directly influences the linewidth and wavelength stability of MEMS lasers. Other microforces, such as radiation pressure, radiometric pressure, and length extension due to thermal heating also determine the wavelength stability during dynamic operation, leading to a micromechanic chirp component. The theoretical analysis is compared directly with the experimental data obtained from measurements with a MEMS vertical-cavity surface-emitting laser (MEMS-VCSEL). The results are in agreement with the data predicted by the modeling and prove the viability of the approach