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Author

Vitalii Sichkovskyi

Bio: Vitalii Sichkovskyi is an academic researcher from University of Kassel. The author has contributed to research in topics: Quantum dot & Quantum dot laser. The author has an hindex of 11, co-authored 50 publications receiving 325 citations. Previous affiliations of Vitalii Sichkovskyi include National Academy of Sciences of Ukraine.


Papers
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Journal ArticleDOI
20 Aug 2019
TL;DR: In this article, the spectral and power characteristics of a single-mode InAs/AlGaInAs/InP QD distributed feedback laser operating at 1.5μm were described.
Abstract: With a new generation of quantum dot (QD) optical gain material comprising atom-like features, the fundamental spectral characteristics of laser emission have been improved significantly. We describe the spectral and power characteristics of continuous wave (CW) single-mode InAs/AlGaInAs/InP QD distributed feedback lasers operating at 1.5 μm. Linewidths as narrow as 60 kHz (30 kHz±10 kHz intrinsic linewidth) at 20°C, which broadens to only 280 kHz (80 kHz±10 kHz intrinsic linewidth) at 80°C, have been achieved. The laser exhibits high output powers of 58 mW at 20°C and 26 mW at 80°C with side mode suppression ratios exceeding 50 dB. These record values stem from high uniformity of the QDs and a large dot density. The linewidth was measured by two techniques that confirm each other: delayed self-heterodyne interferometry and optical frequency comb interferometry. A model fits the experimental results well and enables extraction of the bias and temperature dependent α parameter. At 20°C, α is less than 0.5 at threshold and increases to only 0.9 at 150 mA above threshold. The corresponding values at 80°C are 2 and 2.5. These results imply a great potential of QD lasers for the most demanding applications in terms of spectral purity, such as coherent optical communication systems and optical metrology.

39 citations

Journal ArticleDOI
TL;DR: Direct observations of Rabi oscillations and self-induced transparency in a quantum dot optical amplifier operating at room temperature and a numerical model which solves the Maxwell and Schrödinger equations and accounts for the inhomogeneously broadened nature of the quantum dot gain medium are reported.
Abstract: We report direct observations of Rabi oscillations and self-induced transparency in a quantum dot optical amplifier operating at room temperature. The experiments make use of pulses whose durations are shorter than the coherence time which are characterized using Cross-Frequency-Resolved Optical Gating. A numerical model which solves the Maxwell and Schrodinger equations and accounts for the inhomogeneously broadened nature of the quantum dot gain medium confirms the experimental results. The model is also used to explain the relationship between the observability of Rabi oscillations, the pulse duration and the homogeneous and inhomogeneous spectral widths of the semiconductor.

36 citations

Journal ArticleDOI
TL;DR: In this article, the effect of the number of InAs/InP quantum dot layers (QDLs) on the static parameters of 1.55μm emitting lasers was studied in the range of 1-3 QDLs.
Abstract: The effect of the number of InAs/InP quantum dot layers (QDLs) on the static parameters of 1.55 μm emitting lasers was studied in the range of 1–3 QDLs. Due to the high modal gain of Γg0 ≥ 15.5 cm−1 per QDL ground state lasing of lasers with only a single QDL could be achieved with 11 mW total output power. By optimizing the QDLs number and the cavity length, the temperature dependence of the emission wavelength can be intrinsically stabilized resulting in an ultra-low emission wavelength shift of 0.078 nm/K for a 590 μm long laser with 2 QDLs.

28 citations

Journal ArticleDOI
TL;DR: In this article, a monolithically integrated widely tunable narrow-linewidth light source was realized on an InP-based quantum dot (QD) gain material, which enabled standalone distributed feedback (DFB) lasers with intrinsic linewidths as low as 110 kHz.
Abstract: A monolithically integrated widely tunable narrow-linewidth light source was realized on an InP-based quantum dot (QD) gain material. The quasi zero-dimensional nature of QDs and the resulting low linewidth enhancement factor enabled standalone distributed feedback (DFB) lasers with intrinsic linewidths as low as 110 kHz. An integrated device comprising four DFB lasers with on-chip micro-heaters, a 3 dB-coupler network, and a semiconductor optical amplifier (SOA), which covers the entire C+ telecom band, exhibits a linewidth of below 200 kHz independent of the SOA operation current.

25 citations

Journal ArticleDOI
TL;DR: In this article, the modulation properties and temperature stability of short cavity ridge waveguide lasers based on high-quality InAs quantum dots exhibiting a total modal gain of ~90 cm at room temperature and up to 36 mW are reported.
Abstract: Modulation properties and temperature stability of short cavity ridge waveguide lasers based on high-quality InAs quantum dots exhibiting a total modal gain of ~90 cm -1 are reported. The 338-μm-long lasers show a threshold current of 20 mA at room temperature and an output powers of up to 36 mW. A maximum small signal modulation bandwidth of 15 GHz was obtained at 14 °C, which degrades to 13 GHz at 60 °C and 8 GHz at 80 °C. Digital modulation at 25 Gb/s between 15 °C and 50 °C was obtained with clear open eyes under constant drive conditions (dc and ac). The maximum data rates of 32 and 35 Gb/s were obtained for 338- and 230-μm-long lasers, respectively, at 14 °C.

24 citations


Cited by
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Journal ArticleDOI
TL;DR: In this article, the authors present the most striking recent advances in the field of ultrafast spectroscopy of semiconductors and their nanostructures and present a monograph written by an outstanding expert.
Abstract: This monograph, written by an outstanding expert in time resolved spectroscopy of semiconductors, presents the most striking recent advances in the field of ultrafast spectroscopy of semiconductors and their nanostructures. The book contains 8 chapters with in total 1160 references and 186 figures, preface and subject index. It begins with an introductory chapter on basic concepts of semiconductor physics and ultrafast spectroscopic techniques. The following five chapters are arranged in the order of occurrence of events in a homogeneous semiconductor following photoexcitation by an ultrashort pulse. These events comprise four temporally-overlapping regimes:

342 citations

Journal Article
01 Jan 2004-Physics
TL;DR: The relationship between the Nobel prize for physics and semiconductor science and technology was explored and analyzed in this paper, which has practical importance for our understanding of the development of semiconductor S T and for predicting its future.
Abstract: Semiconductor science and technology (S T) is a very active branch in the field of natural science, and is also a typical example embodying the development of advanced S T. The Nobel prize for physics is a prize of the highest honour in the world, and there are certain relationships between this award and semiconductor S T. We explore and analyze these inherent relationships which have practical importance for our understanding of the development of semiconductor S T and for predicting its future.

194 citations

12 Dec 2003
TL;DR: This paper reviews the recent progress of quantum-dot semiconductor optical amplifiers developed as ultrawideband polarization-insensitive high-power amplifiers, high-speed signal regenerators, and wideband wavelength converters and suggests a potential for low-cost realization of regenerative transmission systems.
Abstract: This paper reviews the recent progress of quantum-dot semiconductor optical amplifiers developed as ultrawideband polarization-insensitive high-power amplifiers, high-speed signal regenerators, and wideband wavelength converters. A semiconductor optical amplifier having a gain of > 25 dB, noise figure of < 5 dB, and 3-dB saturation output power of > 20 dBm, over the record widest bandwidth of 90 nm among all kinds of optical amplifiers, and also having a penalty-free output power of 23 dBm, the record highest among all the semiconductor optical amplifiers, was realized by using quantum dots. By utilizing isotropically shaped quantum dots, the TM gain, which is absent in the standard Stranski-Krastanow QDs, has been drastically enhanced, and nearly polarization-insensitive SOAs have been realized for the first time. With an ultrafast gain response unique to quantum dots, an optical regenerator having receiver-sensitivity improving capability of 4 dB at a BER of 10-9 and operating speed of > 40 Gb/s has been successfully realized with an SOA chip. This performance achieved together with simplicity of structure suggests a potential for low-cost realization of regenerative transmission systems.

160 citations

Journal ArticleDOI
05 Nov 2019
TL;DR: In this paper, the authors discuss in-depth techniques that are used to drastically reduce the linewidth of a laser, and fully integrated laser with Lorentzian linwidth on the order of 100 Hz and tuning range of 120 nm are shown.
Abstract: Narrow linewidth lasers have many applications, such as higher order coherent communications, optical sensing, and metrology. While semiconductor lasers are typically unsuitable for such applications due to relatively low coherence, recent advances in heterogeneous integration of III-V with silicon have shown that this is no longer true. In this tutorial, we discuss in-depth techniques that are used to drastically reduce the linewidth of a laser. The heterogeneous silicon-III/V platform can fully utilize these techniques, and fully integrated lasers with Lorentzian linewidth on the order of 100 Hz and tuning range of 120 nm are shown.

131 citations

Journal ArticleDOI
TL;DR: In this paper, a simple and inexpensive way for the preparation of highly transparent ZnO thin films and their application as active layer in UV ray sensor devices was reported. But this method is not suitable for the case of high temperature.
Abstract: We report a simple and inexpensive way for the preparation of highly transparent ZnO thin films and their application as active layer in UV ray sensor devices. ZnO thin films were deposited on glass substrates by thermal evaporation of pure ZnO powder. The as-deposited films were then annealed at different temperatures (100, 200, 300 and 400 °C) for various time durations (5, 15, 25 and 35 min) to make optically transparent in the visible region. The films annealed at 300 °C for 15 min show very good visible transparency and other material properties. These films were used as the active material for Ag/ZnO/Ag UV sensor devices. The sensor devices are photo conductive type and only sensitive in the UV region of the electromagnetic spectrum. Maximum photo-current gain of the UV sensor device is ∼2. Possible sensing mechanism has been discussed.

114 citations