High efficiency 10-micron-pitch 64x64 addressable VCSEL array with intracavity structure

Abstract

In this paper, we report a high efficiency, addressable 940 nm Vertical-Cavity Surface-Emitting Laser (VCSEL) array with a tight pitch of 10 m for a compact, low-power sensing light source. High electrical resistance of a small diameter semiconductor DBR is a major issue to obtain a high-power conversion efficiency in achieving a tight pitch VCSEL array. We have developed a highly efficient back side emitted VCSEL with intracavity contacted structure, mesa diameter of 7.5 μm, and optical aperture of 3.0 μm. The power conversion efficiency exceeded 30% from 0.5 mW to 3.5 mW in the wide power range. We also report Tx module using this highly efficient VCSEL with a tight pitch of 10 μm. The tight pitch addressable 2D VCSEL array required sophisticated process techniques because they have a small spacing of 2–3 μm between mesas. To improve productivity, we developed a new device structure decreasing the process difficulty between mesas and demonstrated 2D addressable VCSEL array arranged 64 by 64 matrix and 4096 emitters. In addition, we demonstrated addressable operation with assembled sample using Si interposer.