GaN-based Vertical-Cavity Surface-Emitting Lasers Incorporating Dielectric Distributed Bragg Reflectors

Abstract

This paper reviews past research and the current state-of-the-art concerning gallium nitride-based vertical-cavity surface-emitting lasers (GaN-VCSELs) incorporating distributed Bragg reflectors (DBRs). This paper reviews structures developed during the early stages of research into these devices, covering both major categories of GaN-based VCSELs: hybrid-DBR and all-dielectric-DBR. Although both types exhibited satisfactory performance during continuous-wave (CW) operation in conjunction with current injection as early as 2008, GaN-VCSELs have not yet been mass produced for several reasons. These include the difficulty in controlling the thicknesses of nitride semiconductor layers in hybrid-DBR type devices and issues related to the cavity dimensions in all-dielectric-DBR units. Two novel all-dielectric GaN-based VCSEL concepts based on different structures are examined herein. In one, the device incorporates dielectric DBRs at both ends of the cavity, with one DBR embedded in n-type GaN grown using the epitaxial lateral overgrowth technique. The other concept incorporates a curved mirror fabricated on (000-1) GaN. Both designs are intended to mitigate challenges regarding industrial-scale processing that are related to the difficulty in controlling the cavity length, which have thus far prevented practical applications of all-dielectric GaN-based VCSELs.

Progress of GaN‐Based Optoelectronic Devices Integrated with Optical Resonances

“…Hence, extra lifting off and transferring processes are often required for dielectric DBRs, which causes much complexity during production. [ 74 ]…”

Review on Single-Mode Vertical-Cavity Surface-Emitting Lasers for High-Speed Data Transfer

“…Such (AlGa) xOy/GaAs DBRs are called oxidized DBRs. They provide a high level of reflection and a wide reflectance bandwidth while using fewer paired layers, compared to monolithic semiconductor DBRs, which is due to a significant difference in the refractive indices of the materials [44]. However, there is a problem of mechanical stability of such mirrors [45].…”

“…Another type of DBRs is dielectric DBRs, which are made of materials with higher refractive index than monolithic DBRs [44], so fewer paired layers are used to reach effective positive feedback. The most common paired layers are SiO2/TiO2 and SiO2/Ta2O5.…”

Design and simulation of vertical cavity surface emitting laser based on all-inorganic perovskite

“…DFB lasing is more difficult to generate and requires a higher threshold current. While the VCSEL structure consisting of two layers of DBR has the advantages of small divergence angle, low threshold current, single longitudinal mode operation, high-speed modulation, etc [14][15][16][17][18] . VCSEL has been widely used in optical communication, optical storage, laser display, laser sensing and other fields [19][20][21][22][23] .…”