Paper
2 January 1998 Alternative shape for tapered geometry semiconductor optical sources
Alexander I. Onischenko, Jayanta Sarma
Author Affiliations +
Proceedings Volume 3211, International Conference on Fiber Optics and Photonics: Selected Papers from Photonics India '96; (1998) https://doi.org/10.1117/12.345523
Event: International Conference on Fiber Optics and Photonics: Selected Papers from Photonics India '96, 1996, Madras, India
Abstract
Recently a high level of in-plane emission in VCSELs has been reported [1]. Existence of the problem for vertical cavities has been previously demonstrated in connection with electron beam pumped lasers [2] and LED [3]. The effect results in increasing threshold and a reduction of efficiency of the devices [2]. Prili- menary estimation shows importance of the problem for large diameter VCSEL as well [4]. Thus, suppression of the in-plane emission gives a way of improvement of VCSEL operational characteristics. Features of the spontaneous emission (SE) pattern is a basis for simulation and modelling of the effect. In this paper the SE is considered for both A— and A/2— cavities in the framework of a planar multilayer structure model taking into account the QW optical spectrum. The model is suitable for large diameter VCSELs with weak radial boundaries and allows the consideration of both in-plane and vertical propagating modes. Results of calculation show that, for a A/2— cavity, all in-plane propagating modes have weak coupling to a dipole of the active region (QW), unlike the A— cavity case where there is a mode having a field maximum in the position of QW and thus strong dipole coupling. This leads to a 2 - 4 times reduction of spontaneous emission in the in-plane direction for the A/2— cavity. However, this is still comparable with the SE in ”vertical” modes and therefore can not be neglected, as is usually assumed. The ” vertical” modes in general propagate at different angles to the 55 pure vertical direction” and hence have an in-plane component of the propagation constant. Analysis shows the ’’pure” vertical part of the SE to be extremely small compared to the total. Thus, the in-plane component of the SE should be taken into account to improve VCSEL desig
© (1998) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Alexander I. Onischenko and Jayanta Sarma "Alternative shape for tapered geometry semiconductor optical sources", Proc. SPIE 3211, International Conference on Fiber Optics and Photonics: Selected Papers from Photonics India '96, (2 January 1998); https://doi.org/10.1117/12.345523
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KEYWORDS
Vertical cavity surface emitting lasers

Optical semiconductors

Quantum wells

Semiconductors

Electron beams

Light emitting diodes

Modeling

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