High-power single-mode vertical-cavity surface-emitting lasers

Abstract

This letter reports a design for high-power single-mode operation in vertical-cavity surface-emitting lasers by means of modal gain control using two different sized current apertures to shape the injection-current profile. A smaller current aperture is located several mirror-pairs away from the active region in the p-mirror and a larger current aperture is located in the first n-mirror-pair next to the active region. Both theoretical modeling and experimental test results show substantial improvement in the optical mode behavior using this approach when compared to a traditional single-aperture design. A clear trend of the spectral purity in the modal behavior under continuous wave and pulsed conditions is demonstrated and is in good agreement with theoretical predictions. The best design tested demonstrated a room-temperature continuous wave power output of 7.5mW with a side mode suppression ratio of 20dB.

Numerical Self-Consistent Analysis of VCSELs

“…However, the second aperture is located relatively far from the active region. Nevertheless, Samal et al [35] have observed single-fundamental-mode operation of their VCSELs with two oxide apertures, whereas their VCSEL with only one oxide aperture located close to the antinode position emits the high-order LP 31 transverse mode, which is consistent with our model.…”

“…Our theoretical model of the proposed SCO VCSEL configuration is consistent with the experimental work by Samal et al [35]. As in the SCO VCSEL, two apertures of different diameters on both sides of the VCSEL active region are utilized leading to dramatically improved mode selectivity.…”

Widely tunable micro electromechanical systems (MEMS)-vertical-cavity surface-emitting lasers with single transverse mode operation

“…Dynamic of the VCSELs is primarily governed by the following space and time dependent rate equations coupled with thermal equation as follows (Jungo and Erni, 2003;Samal, 2004):…”

“…The modification of Equation (5) begins with separation of the time and space variables. This is done for photon density by describing as azimuthal and radial components of the optical field so-called c and s modes (Jungo and Erni, 2003;Samal, 2004):…”

“…Many approaches to achieve single mode, high temperature, and high power operations have been reported (Zhou and Mawst, 2002). There are different effects such as pump induced current spreading, spatial hole burning and thermal gradients inside the cavity on the carrier distribution which lead to VCSELs multi mode behaviour (Samal et al, 2005;Nakwaski and Sarzala, 1998). Our aim is to optimize a tunable VCSEL based on the GaAs material system with dilute nitride/antimonide quantum wells for the long wavelength.…”