All-Monolithically Integrated Self-Scanning Addressable VCSEL Array for 3D Sensing

Abstract

We propose an all-monolithically integrated self-scanning addressable vertical-cavity surface-emitting laser array for time-of-flight measurement. Some advantages of addressable VCSELs for ToF measurement applications include large reductions in power consumption, heat generation, multi-pass noise, and flare noise. In this paper, we discuss the characteristics of the proposed self-scanning addressable VCSEL array. All layers in the epilayer structure of the proposed VCSEL array were formed at once by metal-organic chemical vapor deposition. The device consists of an (Al)GaAs-based thyristor and a conventional top-emitting 940-nm oxide-confined VCSEL on an n-type GaAs substrate. The array contained 12 blocks (4 × 3) that have more than 40 emitters each. The device required only four signals from a field-programmable gate array to select the emitting blocks and one emission signal from a conventional VCSEL driver, even for arrays containing hundreds of blocks. The proposed module is capable of one-block sequential emission, parallel emission from several blocks, and emission from all blocks. The rise and fall times of the fabricated VCSEL array were observed to be 200 and 400 ps, respectively, for each emission mode. The influence of flare noise from an obstacle in front of the camera was dramatically reduced by avoiding emission to the obstacle.