High-Speed and High-Power 940 nm Flip-Chip VCSEL Array for LiDAR Application

Abstract

In this paper, we demonstrate the design and fabrication of a high-power, high-speed flip-chip vertical cavity surface emitting laser (VCSEL) for light detection and ranging (LiDAR) systems. The optoelectronic characteristics and modulation speeds of vertical and flip-chip VCSELs were investigated numerically and experimentally. The thermal transport properties of the two samples were also numerically investigated. The measured maximum output power, slope efficiency (SE) and power conversion efficiency (PCE) of a fabricated flip-chip VCSEL array operated at room-temperature were 6.2 W, 1.11 W/A and 46.1%, respectively. The measured L-I-V curves demonstrated that the flip-chip architecture offers better thermal characteristics than the conventional vertical structure, especially for high-temperature operation. The rise time of the flip-chip VCSEL array was 218.5 ps, and the architecture of the flip-chip VCSEL with tunnel junction was chosen to accommodate the application of long-range LiDAR. The calculated PCE of such a flip-chip VCSEL was further improved from 51% to 57.8%. The device design concept and forecasting laser characteristics are suitable for LiDAR systems.

Advances in high-power vertical-cavity surface-emitting lasers

“…Zhou et al achieved 5 mm × 5 mm VCSEL arrays emitting at 808 nm with a peak PCE of 51% and peak power of 800 W, corresponding to a peak power density of approximately 4 kW cm of 55 A [102]. Hong et al designed and fabricated a flip-chip VCSEL array [98]. Such flip-chip VCSEL array show a maximum output power of 6.2 W, a SE of 1.11 W A −1 , and a PCE of 46.1%.…”

Inverted n–p junction 940‐nm vertical‐cavity surface‐emitting laser arrays consisting of 875 devices on p‐GaAs substrate

“…For 3D sensing applications, high optical power levels are required to obtain sufficient signal‐to‐noise ratios in bright outside environments [4]. The accurate distance measurement in LiDAR systems requires high‐power density to be capable of creating a 3D representation of a surveyed environment or object with a high level of accuracy in long‐distance detection [5]. VCSELs, similar to most other active photonic devices based on III to V compound semiconductors, usually employ a p–n junction with p‐up and n‐down epitaxial structure on an n‐type substrate.…”

“…Demand for VCSELs has rapidly grown along with their wide range of applications, such as free-space optical communication (FSOC) using VCSELs in the expansion of 5G technology, 3-dimensional (3D) sensing, light detection and ranging (LiDAR), integrated systems of VCSELs and photodetectors etc. [3][4][5][6]. For the growing market of robotics and autonomous vehicles, the optical output power of the VCSELs should be increased to the range of watt (W) from mW (for the case of a single VCSEL) by integrating substantial numbers of VCSELs in a 2D array.…”

Highly efficient thin-film 930 nm VCSEL on PDMS for biomedical applications

“…Vertical cavity surface-emitting laser (VCSEL) has been rapidly emerging as a promising optical source compared to conventional light-emitting diodes (LEDs) and edge-emitting laser diodes (EELs) due to its low-threshold, low-divergence beam size, excellent reliability, and low-power consumption 3 – 6 . Furthermore, it is feasible to fabricate two-dimensional (2D) laser arrays, enabling it to pack easily into optical chips such as photonic integrated circuits (PIC).…”