Inverted Junction VCSEL Arrays Operating at 940 nm with ˃5 W Employing Tunnel Junction

Abstract

We develop inverted n-p junction arrayed vertical-cavity surface-emitting lasers (VCSELs) with 875 devices operating at ∼940 nm, optimized for high optical output power in sensing applications. Employment of an n-type GaAs substrate prevents performance degradation caused by defects in p-type GaAs substrates. A tunnel junction enables polarity inversion. The inverted n-p VCSEL arrays, which are preferred for circuit design and packaging, are compared with conventional p-n junction VCSEL arrays on an n-type substrate using three-dimensional device modeling and experimental measurements. The optical output power of large-area 25×35 VCSEL arrays shows ∼5.5 W at I ≈ 6 A. The threshold current density and slopes of the L-I curve of the inverted n-p VCSEL arrays are ∼1.2 kA/cm2 and 0.98 W/A, respectively, which are similar to those of reference p-n VCSELs. The inverted n-p arrays demonstrate slightly better electrical performance, higher output power, and power conversion efficiency than p-n, enhancing their potential in voltage-controlled sensing systems. This is the first demonstration of the large-area inverted n-p VCSEL arrays, achieving the highest light output power critical for emerging 3D sensing and LiDAR applications. © 1989-2012 IEEE.