The influence of injection current on transverse mode characteristics of vertical-cavity surface-emitting lasers

Abstract

The influence of transverse mode were researched with the injection current changing via experiments conducted with 980nm oxide-confined vertical cavity surface emitting lasers (VCSELs). Based on the spatio-temporal rate equation, the injection parameter dependence of the transverse mode characteristics of weak-index guiding VCSELs were theoretically researched by integrating the spatially dependent part. The result of the experiment indicated that the higher-order modes begin to emerge and exhibit strong competition with the injection current increased when the oxidized aperture was kept unchanged, and the distribution of the carrier transfers from the center to the edge. Furthermore, the main order becomes weaker because of the spatial hole burning. Compared with the appearance of higher-order modes with different oxidized aperture, the small injection aperture exhibits better single mode behavior.

A low-threshold and high-power oxide-confined 850-nm AlInGaAs strained quantum-well vertical-cavity surface-emitting laser

“…[1−3] Commercial competition has promoted extensive studies of the basic theory and technology for these devices in order to improve the quantum efficiency and to reduce the threshold current (I th ) for high-speed modulation. [4,5] However, there are difficulties with the physical aspects of the device, such as the alignment of the gain peak, the cavity resonant peak and the distributed Bragg reflector (DBR) reflective centre, which are governed by the material growth and the improvement of the single round-trip optical gain, thereby making the VCSEL device difficult to fabricate. In addition, in the case of large active regions, hardly any current can reach the broad central active region and the injection is mostly restricted to a narrow ring area close to the active-region perimeter.…”