Anagnostis Paraskevopoulos - Academia.edu (original) (raw)

Papers by Anagnostis Paraskevopoulos

International Conference on Indium Phosphide and Related Materials, 2005., 2005

Buried heterostructure (BH) electroabsorption (EA) modulators completely grown by LP-MOVPE presen... more Buried heterostructure (BH) electroabsorption (EA) modulators completely grown by LP-MOVPE present advantages of robust single mode and better thermal behavior over standard ridge structures. However, without special care, strong morphological difficulties after MOVPE regrowth and high leakage current with excess junction capacitance are often observed forbidding early technological steps in the fabrication process or the realization of reliable components. To

In this paper we report on invertible DHBTs fabricated on GaInAsP/InP. Localized Zn diffusion all... more In this paper we report on invertible DHBTs fabricated on GaInAsP/InP. Localized Zn diffusion allowed for practically equal active transistor areas in the forward and inverse mode. Transit frequencies up to 6 GHz with collector currents over 100mA could be demonstrated on these devices. As an application, three transistors were monolithically integrated to form a laser driver circuit showing modulation rates up to 2.6 Gbit/s.

Experimental results with a secondary ion mass spectroscopy in situ monitoring system for ion bea... more Experimental results with a secondary ion mass spectroscopy in situ monitoring system for ion beam etching are described. The authors demonstrate that the sensitivity of this method is high enough to monitor the dry etching of any type of semiconductor material in the InP/InGaAsP and GaAs/AlAs basis with both the commonly used etch gases, N2 and Ar. The technique enables the precise control of metal contact dry etching. Layers of a thickness as low as 2.5 nm for a minimum etched surface of only 15 mm2 were resolved

Selective regrowth of Fe-doped InP by tertiarybutylchloride (TBCl) assisted low pressure MOVPE on... more Selective regrowth of Fe-doped InP by tertiarybutylchloride (TBCl) assisted low pressure MOVPE on tall and narrow ridges has been investigated regarding the chloride addition, the surface morphology, and the mesa shape. Planarisation experiments have been carried out on ridges orientated in the (110) direction on (100) InP:Sn substrate. An excess growth ratio as low as 6 % was achieved on 1.5 µm wide - 3 µm high mesas. The planarisation effect was found to depend mainly on the chloride concentration during the selective growth. Thus, we were able to demonstrate the establishment of a successful planarisation process by means of TBCl addition, essential to the fabrication of high speed optoelectronic devices

Conference on Lasers and Electro-Optics Europe, 1994

Conference Proceedings. 1997 International Conference on Indium Phosphide and Related Materials, 1997

High-quality InP material was grown with solid source molecular beam epitaxy (SSMBE) using a GaP ... more High-quality InP material was grown with solid source molecular beam epitaxy (SSMBE) using a GaP source. Dry- as well as wet-etched corrugated quaternary surfaces (DFB-gratings) were successfully regrown with InP, fully planarized final surfaces were obtained in each case. Finally, InP regrowth on mesa structures demonstrates favourable conditions for butt-coupling integration schemes

2009 International Symposium on Optomechatronic Technologies, 2009

For future short-and mid-range industrial applications, optical free-space communication systems ... more For future short-and mid-range industrial applications, optical free-space communication systems are expected to play a major role. When moderate transmission rates (100 Mbps range) are required, optical wireless communications present a viable and promising technology supplemental to conventional radio wireless systems. Advanced approaches based on diversity techniques and adaptive signal processing show potential to achieve both high spatial coverage and high bit rates of more than 100 Mbps. Visible light communication systems using white phosphorescent LEDs present equally an interesting application potential, combining illumination with data transfer. When high data volumes (100 Gbps range) need to be transmitted, tailored optical data links provide a solution of choice. Exemplarily, a scalable (24 -140 Gbps) optical data link is presented, developed for future implementation in maskless lithography systems. The link comprises a high-speed data buffer with synchronizable architecture and scalable throughput (N x 24 Gbps), an optical free space transmission solution, and, finally, a 45 channel lownoise optical receiver chip based on BiCMOS 0.6 µm technology.

2011 13th International Conference on Transparent Optical Networks, 2011

This paper reviews the main experimental results achieved by our research group in the area of hi... more This paper reviews the main experimental results achieved by our research group in the area of high-speed wireless visible light communication (VLC). Depending on the modulation complexity and receiver sensitivity, various links operating at rates in the range of 10 – 800 Mbit/s have been demonstrated using off-the-shelf optical components.

16th IPRM. 2004 International Conference on Indium Phosphide and Related Materials, 2004., 2004

Planarization of semi-insulating InP by TBCl assisted LP-MOVPE has been achieved on high (> 5 ... more Planarization of semi-insulating InP by TBCl assisted LP-MOVPE has been achieved on high (> 5 μm) ridges. Full planarization at the whole width between adjacent ridges was obtained for various epitaxial conditions and independent form the ridge form. Fabrication of first modulator devices confirms the high potential of this technique for the development of high-speed optoelectronic components.

2006 Optical Fiber Communication Conference and the National Fiber Optic Engineers Conference, 2006

Electrical bandwidth of 60 GHz and optical bandwidth exceeding 35 GHz, limited by the photodetect... more Electrical bandwidth of 60 GHz and optical bandwidth exceeding 35 GHz, limited by the photodetector response, are demonstrated for an electrooptically-modulated VCSEL. The maximum single mode power approaches 3mW continuous wave. Modulation voltage efficiency factor is 3-10 dB/V.

2012 14th International Conference on Transparent Optical Networks (ICTON), 2012

ABSTRACT For the first time, we present optimized indoor visible light links at up to 806 Mbit/s ... more ABSTRACT For the first time, we present optimized indoor visible light links at up to 806 Mbit/s using a single channel of a low-cost off-the-shelf RGB-LED. While the RGB-LED acts as transmitter, a high bandwidth Si-PIN photodiode is used at the receiver. Discrete multitone modulation (DMT) is applied to optimally adapt to the channel corresponding to each color. With illumination levels in the range of normal working environments at the receiver, the resultant BERs are below the forward-error-correction limit for standard correction mechanisms.

LEOS 2001. 14th Annual Meeting of the IEEE Lasers and Electro-Optics Society (Cat. No.01CH37242), 2001

Dry etched facets remain a very attractive task in the semiconductor laser diode fabrication, as ... more Dry etched facets remain a very attractive task in the semiconductor laser diode fabrication, as they can potentially lead to on-wafer device fabrication including preliminary testing, allowing thus a substantial cost reduction. Chemically assisted ion beam etching (CAIBE) technique is commonly applied to this aim, as it allows for vertical sidewall etching combined with high etch rates. However, while on the GaAlAs/GaAs basis some quite convincing results were achieved (Unger et al., 1993), this seems not to be the case for the InGaAsP/InP laser devices to the same extent. Published results were obtained either at low temperature etching (5°C) with IBr3 as a chemical component (Eisele et al., 1996), or at higher temperatures (250-300°C) with Cl2 using multilayer masks or thick (700 nm) SiO2 (Youtsey et al., 1994; Dzioba et al., 1993; Tsang et al., 1999). In this paper we present, to our knowledge for the first time, results on ridge waveguide (RW) lasers with dry etched laser facets using a simple photoresist mask, without any additional treatment after the lithographic exposure. We demonstrate that the fabricated devices show identical characteristics to those of lasers with cleaved facets

ESSDERC ’89, 1989

ABSTRACT An integrated laser driver circuit representing a step towards a monolithic optical tran... more ABSTRACT An integrated laser driver circuit representing a step towards a monolithic optical transmitter was fabricated on InGaAsP/InP employing invertible double-heterojunction bipolar transistors. Static transconductance of up to 200 mS was attained. Well-behaved eye pattern diagrams have been demonstrated at modulation rates of as high as 1.12 Gbit/s.

Journal of Vacuum Science & Technology B: Microelectronics and Nanometer Structures, 1998

ABSTRACT Fabrication of a prototype Ga0.47In0.53As/Al0.48In0.52As/InP double heterojunction bipol... more ABSTRACT Fabrication of a prototype Ga0.47In0.53As/Al0.48In0.52As/InP double heterojunction bipolar transistor employing an embedded n+/n--InP:Si subcollector/collector region in an otherwise semi-insulating InP:Fe substrate was studied. The basic layer structure was accomplished by two sequential growth cycles on the basis of device quality Al0.48In0.52As/Ga0.47In0.53As grown by molecular beam epitaxy (MBE) and InP grown by metalorganic molecular beam epitaxy (MOMBE). For the first time the embedded collector was implemented by truly selective infill growth into a substrate groove with vertical sidewalls defined by reactive ion etching (RIF) using MOMBE. Excellent layer morphology in combination with lateral interfaces without growth irregularities at the lateral substrate/collector interface were achieved in the [0-1-1] direction, while some minor facet formation due to slightly enhanced growth rates appeared in the [0-11] direction. The device layer stack was completed by large area Al0.48In0.52As/Ga0.47In0.53As MBE regrowth due to its ability to highly Be dope the GaInAs base when grown at reduced growth temperatures. Functional devices were obtained. Some degradation in the output characteristics could be directly correlated with inhomogeneities in the MBE regrown structure. © 1998 American Vacuum Society.

Microelectronic Engineering - MICROELECTRON ENG, 1991

A model is developed describing Zn outdiffusion during epitaxial growth of a Double Heterostructu... more A model is developed describing Zn outdiffusion during epitaxial growth of a Double Heterostructure Bipolar Transistor (DHBT) structure. This model is used for the design of the highly p-doped base layer. Experimental results confirm the calculated doping profiles.