Tunable MEMS-VCSEL with High-Contrast Grating

We design and fabricate a tunable micro-electro-mechanical system (MEMS) vertical-cavity surface-emitting laser (VCSEL) at 940-nm range. The MEMS-VCSEL uses a movable high-contrast grating (HCG) mirror to replace the top semiconductor distributed Bragg reflector (DBR) of the common VCSEL. By applying a reverse voltage across the air layer, the HCG moves downward under the electrostatic force, thereby changing the wavelength of the MEMS-VCSEL. Theoretically, the MEMS-VCSEL with this structure can achieve a maximum wavelength tuning range of over 30 nm. At present, we have realized a tuning range of 3.7 nm at room temperature.

I. Introduction

With the rapid development of optical communication technology, high-performance vertical-cavity surface-emitting lasers (VCSELs) have become key devices for the high-speed and high-density optical interconnects. The structure of a VCSEL is mainly composed of an active region, an oxide aperture, a top reflector, and a bottom reflector [1]–[3]. VCSELs have many advantages such as low threshold current, low power consumption, small beam divergence angle, circular symmetrical spot, dynamic single longitudinal mode, easy two-dimensional integration, and on-wafer testing. At present, VCSELs have been widely used in optical interconnects, sensing, light detection and ranging (LiDAR), and so on [4]–[6].