Prof. Lukas W. Snyman Profile

Prof. Lukas W. Snyman

Professor at Univ of South Africa

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Author

Publications (27)

SPIE Journal Paper | 28 December 2022

Realization of GHz band integrated optical links in a radio frequency Si Ge bipolar process operating at 650 to 850 nm wavelength

Lukas Snyman, Kingsley Ogudo, Zerihun Tegnege, Jean-Luc Polleux, Anne-Laure Billabert, Herzl Aharoni

OE, Vol. 61, Issue 12, 125109, (December 2022) https://doi.org/10.1117/12.10.1117/1.OE.61.12.125109

KEYWORDS: Silicon, Waveguides, Integrated optics, Radio optics, Germanium, Light emitting diodes, CMOS technology, Silicon nitride, Sensors, Design

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Proceedings Article | 24 January 2019 Paper

Light emission from Si avalanche mode LEDs as a function of E field control, impurity scattering, and carrier density balancing

Zhaotong Zhang, Kingsley Ogudo, Hongliang Sun, Lukas Snyman, Kaikai Xu

Proceedings Volume 11043, 1104307 (2019) https://doi.org/10.1117/12.2502224

KEYWORDS: Silicon, Scattering, Electrons, Light emitting diodes, Light scattering, Control systems, Integrated optics, Photonics, Ionization

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Proceedings Article | 24 January 2019 Paper

Design and simulation of optical micro-structures in silicon integrated circuitry with Si avalanche-mode light emitters, EXCEL optical ray tracing, and RSOFT optical simulation

Lukas Snyman, Timothy Okhai

Proceedings Volume 11043, 110430M (2019) https://doi.org/10.1117/12.2502061

KEYWORDS: Silicon, Waveguides, Geometrical optics, Light emitting diodes, Wave propagation, Interfaces, Integrated optics, Ray tracing, Refractive index, Integrated circuit design

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Proceedings Article | 24 January 2019 Paper

A low cost thermal energy absorber for rural Africa applications: isolation of high pressure and low pressure through heat exchanging

Monga Twite, Kevin Jalet, Lukas Snyman

Proceedings Volume 11043, 110430W (2019) https://doi.org/10.1117/12.2502067

KEYWORDS: Copper, Solar energy, Patents, Switches, Temperature metrology, Solar cells, Solar energy systems, Relays, Control systems, Intellectual property

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A low-cost heat exchanger system was developed that enable the realization of high pressure, low pressure isolated solar water heating systems in Africa. Africa countries are mostly located mid equatorial and has superfluous resources of solar and thermal energy. The design comprised of a copper coil based heat exchange system that can replace the normal heating element and thermostat in a conventional household geyser. The circulation in the system is performed by a small separate photovoltaic panel and circulation pump. The exchanger allows for isolation of the high pressure and low pressure sections of a normal household geyser system and enable the utilization of very large, low cost solar heat absorber platforms. This feature remarkably increasing the heat collection capacity of the system. An integrated switch allows the system to alternate between conventional electrical heating and solar water heating, according to prevailing weather conditions. A smart sensor system monitor absorber and ambient temperatures continuously, and controls switch on times and circulation rates according to prevailing weather conditions, and in order to optimize thermal energy collection. The system can be installed at approximately 10 000 -12 000 SA Rand. Calculations show that the system can provide hot water to a household in South Africa at approximately 0. 12 SA rand per kWh, implying a saving to current customer that uses grid electricity at approximately R600 per month (weather depending). The accumulated saving to the household owner is of the order of 200 000 SA Rand over a ten year lifetime period for the product. The system offers numerous new business opportunities and job creation opportunities in South Africa. It is believed that the technology can be supplied and products can be provided to other international countries outside of South Africa. In this case the international countries can draw advantage from the technology as developed in South Africa, and can import products at reduced (very low costs ) drawing on the advantageous of an extreme favorable exchange rates, reduced import levies, while providing dire job opportunities in an developing African countries.

Proceedings Article | 24 January 2019 Paper

Edge-emitting Si avalanche-mode LED integrated into a SiGe RF bipolar technology: optical power emission characterization with optical probe mapping technique

Kingsley Ogudo, Jean-Luc Polleux, Lukas Snyman

Proceedings Volume 11043, 1104309 (2019) https://doi.org/10.1117/12.2502515

KEYWORDS: Light emitting diodes, Silicon, Waveguides, Sensors, Integrated optics, Light, Wafer-level optics, Optical power meters, Optical design, Optical testing

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A novel silicon SiGe edge light emitting diode (SiGe ELED) was realized in standard RF bipolar SiGe technology process that uses a p-n junction either in reverse and forward bias mode configurations. A vertical cubical columnar SiGe/Si HBT like structure was used. The light emitting process in the reverse bias mode is by means of an avalanche breakdown process. The reverse biased device emits light in the wavelength range of 450–650 nm, with operating voltage and current of 1.3 V and 8 mA respectively, while the forward biased mode emitted at about 850nm. In the forward biased mode, it operates in a two junction mode with the first n+p junction emitting low energy electrons into a lowly doped p region. The SiGe ELED is intended to be implemented in an optical interconnect with an external detector via a lateral optical waveguide coupling. Because the LED emit in a broad spectrum, localizing the emission source point is of paramount importance. Two techniques were used to attempt to realise this objective. Optical Probe measurement and Optical Power Meter Mapping technique. Localization of the emission source point process was performed through scanning a lensed fiber coupled to an optical power meter, over the edge surface profile of the diced device. The side edge of the diced device structure was interface with the lens fibre in other to ascertain the maximum emission point and the nature of light emitting process. This was done using a smooth dicing of the LED device close to its emitting edge and scanning its edge surface through a multimode lensed fiber coupled to an optical power meter. The mapping area scanned was 40μm x 40μm and 60μ x 60μ to localize the emitting source point region. A total emitted optical power as measured from the Led was 2.86nW as measured by the optical power meter connected to the lensed optical fibre. This was confirmed with a light-current-voltage (LIV) characteristics power measurement curve obtained from the device by means of the edge mapping techniques. A rough estimated localization of the source point was approximately 0.3mW optical power with a current of 8mA was realized with this technique. These results can be used to design accurate electro-optical conversions in integrated photonic circuitry as well as designing well coupled optical interconnects from the chip to the environment.

Proceedings Article | 24 January 2019 Paper

Realizing micro- and nano-optical bio sensors on chip

Timothy Okhai, Lukas Snyman

Proceedings Volume 11043, 1104308 (2019) https://doi.org/10.1117/12.2502491

KEYWORDS: Silicon, Waveguides, Sensors, Biosensors, Light emitting diodes, Transducers, Refractive index, Geometrical optics, Waveguide sensors, Receptors

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SPIE Journal Paper | 18 January 2019

Wavelength dispersion phenomena observed for emitted optical radiation from a p+nn+ silicon avalanche mode light-emitting device in a radio frequency bipolar-integrated circuitry

Timothy Okhai, Lukas Snyman, Jean-Luc Polleux

OE, Vol. 58, Issue 01, 017104, (January 2019) https://doi.org/10.1117/12.10.1117/1.OE.58.1.017104

KEYWORDS: Silicon, Wave propagation, Interfaces, Dispersion, Light emitting diodes, Geometrical optics, Oxides, Refractive index, Refraction, Optical engineering

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Proceedings Article | 3 February 2017 Paper

Wavelength dispersion characteristics of integrated silicon avalanche LEDs: potential applications in futuristic on-chip micro- and nano-biosensors

Timothy Okhai, Lukas Snyman, Jean-Luc Polleux

Proceedings Volume 10036, 1003604 (2017) https://doi.org/10.1117/12.2264200

KEYWORDS: Silicon, Light emitting diodes, Refractive index, Solids, Sensors, Interfaces, Biosensors, Absorption, Integrated circuits, Dispersion

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Proceedings Article | 3 February 2017 Paper

Stimulation of 450, 650 and 850-nm optical emissions from custom designed silicon LED devices by utilizing carrier energy and carrier momentum engineering

L. Snyman, J-L. Polleux, K. Xu

Proceedings Volume 10036, 1003603 (2017) https://doi.org/10.1117/12.2264197

KEYWORDS: Silicon, Electrons, Light emitting diodes, Scattering, Ionization, Photonics, Resistors, Doping, Light scattering, Control systems

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Proceedings Article | 6 November 2015 Paper

Light emission in silicon: from device physics to applications

Kaikai Xu, Ning Ning, Kingsley Ogudo, Jean-Luc Polleux, Qi Yu, Lukas Snyman

Proceedings Volume 9667, 966702 (2015) https://doi.org/10.1117/12.2199841

KEYWORDS: Silicon, Electrons, Electro optics, Photons, Light emitting diodes, Optical interconnects, Photonic integrated circuits, Integrated circuits, Diodes, Chemical species

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Proceedings Article | 23 June 2014 Paper

Realization of 10 GHz minus 30dB on-chip micro-optical links with Si-Ge RF bi-polar technology

Kingsley Ogudo, Lukas Snyman, Jean-Luc Polleux, Carlos Viana, Zerihun Tegegne

Proceedings Volume 9257, 92570I (2014) https://doi.org/10.1117/12.2064737

KEYWORDS: Silicon, Waveguides, Sensors, Light emitting diodes, CMOS technology, Modulation, CMOS sensors, Germanium, Oxides, Integrated optics

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Proceedings Article | 8 March 2014 Paper

High-intensity 100-nW 5GHz silicon avalanche LED utilizing carrier energy and momentum engineering

Lukas Snyman, Jean-Luc Polleux, Kingsley Ogudo, Carlos Viana, Sebastain Wahl

Proceedings Volume 8990, 89900L (2014) https://doi.org/10.1117/12.2038195

KEYWORDS: Silicon, Electrons, Light emitting diodes, Scattering, Sensors, Photonics, Waveguides, Doping, Ionization, Chemical species

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Proceedings Article | 8 March 2014 Paper

Towards 10-40 GHz on-chip micro-optical links with all integrated Si Av LED optical sources, Si N based waveguides and Si-Ge detector technology

Kingsley Ogudo, Lukas Snyman, Jean-Luc Polleux, Carlos Viana, Zerihun Tegegne, Diethelm Schmieder

Proceedings Volume 8991, 899108 (2014) https://doi.org/10.1117/12.2038079

KEYWORDS: Silicon, Waveguides, Sensors, Light emitting diodes, CMOS technology, Modulation, CMOS sensors, Germanium, Integrated optics, Oxides

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SPIE Journal Paper | 6 March 2013 Open Access

Optical propagation and refraction in silicon complementary metal–oxide–semiconductor structures at 750 nm: toward on-chip optical links and microphotonic systems

Kingsley Ogudo, Diethelm Schmieder, Daniel Foty, Lukas Snyman

JM3, Vol. 12, Issue 01, 013015, (March 2013) https://doi.org/10.1117/12.10.1117/1.JMM.12.1.013015

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Proceedings Article | 14 February 2011 Paper

Development of on-CMOS chip micro-photonic and MOEMS systems

Lukas Snyman, Timothy Okhai, Tarik Bourouina, Wilfried Noell

Proceedings Volume 7930, 79300Z (2011) https://doi.org/10.1117/12.873353

KEYWORDS: Silicon, CMOS technology, Waveguides, Light emitting diodes, Sensors, CMOS sensors, Computer aided design, Wave propagation, Integrated optics, Microopto electromechanical systems

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Proceedings Article | 17 January 2011 Paper

Development of a 0.75 micron wavelength, all-silicon, CMOS-based optical communication system

Lukas Snyman, Kingsley Ogudo, Daniel Foty

Proceedings Volume 7943, 79430K (2011) https://doi.org/10.1117/12.873202

KEYWORDS: Silicon, Waveguides, CMOS technology, Light emitting diodes, Sensors, Telecommunications, Oxides, Optical communications, CMOS sensors, Wave propagation

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Proceedings Article | 17 February 2010 Paper

New interpretation of photonic yield processes (450-750nm) in multi-junction Si CMOS LEDs: simulation and analyses

Lukas Snyman, Enrico Bellotti

Proceedings Volume 7606, 760613 (2010) https://doi.org/10.1117/12.843134

KEYWORDS: Silicon, Electrons, Light emitting diodes, Interfaces, CMOS technology, CMOS sensors, Electro optical modeling, Instrument modeling, Standards development, Phonons

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Proceedings Article | 24 February 2009 Paper

Application of Si LEDs (450nm-750nm) in CMOS integrated circuitry-based MOEMS: simulation and analysis

Lukas Snyman, Kingsley Ogudo, Monuko du Plessis, Gustav Udahemuka

Proceedings Volume 7208, 72080C (2009) https://doi.org/10.1117/12.808551

KEYWORDS: Silicon, Light emitting diodes, Integrated circuits, Integrated optics, CMOS technology, Integrated circuit design, Sensors, Oxides, Microopto electromechanical systems, CMOS sensors

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Proceedings Article | 26 February 2008 Paper

Increasing the efficiency of p+np+ injection-avalanche Si CMOS LEDs (450nm – 750nm) by means of depletion layer profiling and reach-through techniques

Lukas Snyman, Monuko du Plessis

Proceedings Volume 6898, 68980E (2008) https://doi.org/10.1117/12.760038

KEYWORDS: Silicon, Electrons, Light emitting diodes, CMOS technology, Profiling, Interfaces, Quantum efficiency, Chemical species, Phonons, Absorption

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Proceedings Article | 1 March 2007 Paper

Two order increase in the optical emission intensity of CMOS Integrated Circuit Si LED’s (450nm – 750nm). Injection–avalanche based n+pn and p+np designs

Lukas Snyman, Monuko du Plessis, Herzl Aharoni

Proceedings Volume 6477, 64770T (2007) https://doi.org/10.1117/12.702292

KEYWORDS: Silicon, Electrons, Light emitting diodes, Integrated optics, Integrated circuits, CMOS technology, Quantum efficiency, Control systems, Standards development, Chemical species

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Proceedings Article | 7 March 2005 Paper

Higher efficiency silicon CMOS light-emitting devices (450nm – 750nm) using current density and carrier injection techniques

Lukas Snyman, Monuko du Plessis, Herzl Aharoni

Proceedings Volume 5730, (2005) https://doi.org/10.1117/12.590553

KEYWORDS: Silicon, Quantum efficiency, Electrons, Integrated circuits, Integrated circuit design, Interfaces, CMOS technology, CMOS sensors, Integrated optics, Optical testing

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Proceedings Article | 1 July 2004 Paper

200-Mbps optical integrated circuit design and first iteration realizations in 1.2- and 0.8-micron Bi-CMOS technology

Lukas Snyman, C.-T. Chaing, Alfons Bogalecki, Monuko Du Plessis, Herzl Aharoni

Proceedings Volume 5357, (2004) https://doi.org/10.1117/12.530733

KEYWORDS: Silicon, Sensors, Integrated optics, CMOS sensors, Signal detection, CMOS technology, Photonic integrated circuits, Optical amplifiers, Light sources, Oxides

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SPIE Journal Paper | 1 October 2003

Planar light-emitting electro-optical interfaces in standard silicon complementary metal oxide semiconductor integrated circuitry

Lukas Snyman, Monuko du Plessis, Herzl Aharoni

OE, Vol. 41, Issue 12, (October 2003) https://doi.org/10.1117/12.10.1117/1.1520541

KEYWORDS: Silicon, Interfaces, Electro optics, Integrated circuit design, Integrated circuits, CMOS technology, Quantum efficiency, Integrated optics, External quantum efficiency, Standards development

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Proceedings Article | 18 May 2001 Paper

Increased electroluminescence from a two-junction Si n+pn CMOS structure

Jerry Matjila, Lukas Snyman

Proceedings Volume 4293, (2001) https://doi.org/10.1117/12.426933

KEYWORDS: Silicon, Electrons, Electroluminescence, Interfaces, Luminescence, Light emitting diodes, Quantum efficiency, Quantum dot light emitting diodes, Photomicroscopy, Visible radiation

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Proceedings Article | 15 March 2000 Paper

Optical sources, integrated optical detectors, and optical waveguides in standard silicon CMOS integrated circuitry

Lukas Snyman, Herzl Aharoni, Alice Biber, Alfons Bogalecki, Lyndsay Canning, Monuko du Plessis, Petrus Maree

Proceedings Volume 3953, (2000) https://doi.org/10.1117/12.379613

KEYWORDS: Silicon, Sensors, CMOS sensors, Integrated optics, Waveguides, Integrated circuit design, Oxides, Interfaces, Light sources, Light

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SPIE Journal Paper | 1 July 1998

Increased efficiency of silicon light-emitting diodes in a standard 1.2-um silicon complementary metal oxide semiconductor technology

Lukas Snyman, Herzl Aharoni, Monuko du Plessis, Rudolph Gouws

OE, Vol. 37, Issue 07, (July 1998) https://doi.org/10.1117/12.10.1117/1.601792

KEYWORDS: Silicon, Light emitting diodes, Quantum efficiency, Interfaces, CMOS technology, Photomicroscopy, Electro optics, External quantum efficiency, Doping, Integrated circuit design

Proceedings Article | 22 September 1997 Paper

Properties of light emission from silicon junctions

Herzl Aharoni, Monuko du Plessis, Lukas Snyman

Proceedings Volume 3110, (1997) https://doi.org/10.1117/12.281338

KEYWORDS: Silicon, Light emitting diodes, Lithium, Thermal effects, Liquid crystal on silicon, Light, LED displays, Light sources, Sensors, Silicon photomultipliers

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Showing 5 of 27 publications

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