Image:Real vcsel.svg

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[edit] Summary

Diagram of a VCSEL structure reported by a highly respected university research lab in 1995.

The structure was reported in

Goobar, E., C. Mahon, F. H. Peters, M. G. Peters, and L. A. Coldren, "Low-temperature operation of vertical cavity surface-emitting lasers", IEEE Photonics Technology Letters, vol. 7, no. 1, pp. 7–9. Jan., 1995.

The detail of the number of repetitions of the upper reflector is taken from a different publication of the same research group in the same year.

The optical guiding method is described as "index-guided", probably meaning that these were air-post type VCSELS. The paper describes devices with diameters of 2 and 6 µm. The InGaAs QW active region gives a long wavelength emission which is not abosorbed by the surrounding GaAs and AlGaAs structure. Optical emission is from the bottom facet, thus through the GaAs substrate.

This device does not use any oxide current-confinement layers, which were a relatively new and important research topic at the time. Oxide confinement is used to restrict the flow of electrical current to the center of the optical mode, reducing the threshold current. The report also does not describe any composition grading, although other papers from this group in 1995 did report graded mirror transitions. Composition grading can reduce the forward voltage required to bias the device, and reduce the energy lost in driving current through the reflector layers.

[edit] Licensing

I, the creator of this work, hereby grant the permission to copy, distribute and/or modify this document under the terms of the GNU Free Documentation License, Version 1.2 or any later version published by the Free Software Foundation; with no Invariant Sections, no Front-Cover Texts, and no Back-Cover Texts.
Subject to disclaimers.

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(del) (cur) 03:51, 28 November 2005 . . The Photon (Talk | contribs) . . 720×540 (85,406 bytes) (Diagram of a research-lab VCSEL structure from 1995.)