Prof. Nikolai N. Ledentsov Profile

Prof. Nikolai N. Ledentsov

Chief Executive Officer at VI Systems GmbH

SPIE Involvement:

Conference Program Committee | Conference Chair | Author

Publications (89)

PROCEEDINGS ARTICLE | February 19, 2018

Temperature stable oxide-confined 850-nm VCSELs operating at bit rates up to 25 Gbit/s at 150ºC

Proc. SPIE. 10552, Vertical-Cavity Surface-Emitting Lasers XXII

KEYWORDS: Oxides, Multimode fibers, Eye, Waveguides, Data transmission, Fiber lasers, Near field, Vertical cavity surface emitting lasers, Data communications, Temperature metrology

Read Abstract

PROCEEDINGS ARTICLE | February 19, 2018

Thermally stable surface-emitting tilted wave laser

Proc. SPIE. 10552, Vertical-Cavity Surface-Emitting Lasers XXII

KEYWORDS: Semiconductors, Refractive index, Waveguides, Electroluminescence, Near field, Vertical cavity surface emitting lasers

Read Abstract

Novel lasing modes in a vertical-cavity surface-emitting laser (VCSEL)-type structure based on an antiwaveguding cavity are studied. Such a VCSEL cavity has an effective refractive index in the cavity region lower than the average index of the distributed Bragg reflectors (DBRs). Such device in a stripe geometry does not support in–plane waveguiding mode, and all modes with a high Q-factor are exclusively VCSEL-like modes with similar near field profile in the vertical direction. A GaAlAs–based VCSEL structure studied contains a resonant cavity with multiple GaInAs quantum wells as an active region. The VCSEL structure is processed as an edge-emitting laser with cleaved facets and top contact representing a non–alloyed metal grid. Rectangular-shaped ~400x400 µm pieces are cleaved with perpendicular facets. The contact grid region has a total width of ~70 μm. 7 μm–wide metal stripes serve as non–alloyed metal contact and form periodic rectangular openings having a size of 10x40 μm. Surface emission through the windows on top of the chip is measured at temperatures from 90 to 380 K. Three different types of modes are observed. The longest wavelength mode (mode A) is a VCSEL–like mode at ~854 nm emitting normal to the surface with a full width at half maximum (FWHM) of the far field ~10°. Accordingly the lasing wavelength demonstrates a thermal shift of the wavelength of 0.06 nm/K. Mode B is at shorter wavelengths of ~840 nm at room temperature, emitting light at two symmetric lobes at tilt angles ~40° with respect to the normal to the surface in the directions parallel to the stripe. The emission wavelength of this mode shifts at a rate 0.22 nm/K according to the GaAs bandgap shift. The angle of mode B with respect to the normal reduces as the wavelength approaches the vertical cavity etalon wavelength and this mode finally merges with the VCSEL mode. Mode B hops between different lateral modes of the VCSEL forming a dense spectrum due to significant longitudinal cavity length, and the thermal shift of its wavelength is governed by the shift of the gain spectrum. The most interesting observation is Mode C, which shifts at a rate 0.06 nm/K and has a spectral width of ~1 nm. Mode C matches the wavelength of the critical angle for total internal reflection for light impinging from semiconductor chip on semiconductor/air interface and propagates essentially as an in–plane mode. According to modeling data we conclude that the lasing mode represents a coupled state between the TM–polarized surface–trapped optical mode and the VCSEL cavity mode. The resulting mode has an extended near field zone and low propagation losses. The intensity of the mode drastically enhances once is appears at resonance with Mode B. A clear threshold is revealed in the L–I curves of all modes and there is a strong competition of the lasing mechanisms once the gain maximum is scanned over the related wavelength range by temperature change.

PROCEEDINGS ARTICLE | February 19, 2018

50 Gb/s NRZ and 4-PAM data transmission over OM5 fiber in the SWDM wavelength range

Proc. SPIE. 10552, Vertical-Cavity Surface-Emitting Lasers XXII

KEYWORDS: Multimode fibers, Eye, Digital signal processing, Modulation, Signal attenuation, Dispersion, Data transmission, Picosecond phenomena, Vertical cavity surface emitting lasers, Forward error correction

Read Abstract

PROCEEDINGS ARTICLE | August 7, 2017

High speed data transmission with a modal filter

Proc. SPIE. 10445, Photonics Applications in Astronomy, Communications, Industry, and High Energy Physics Experiments 2017

KEYWORDS: Multimode fibers, Optical filters, Eye, Signal attenuation, Manufacturing, Data transmission, Fiber lasers, Signal processing, Vertical cavity surface emitting lasers, Electronic filtering

Read Abstract

PROCEEDINGS ARTICLE | February 25, 2017

Single-mode 850-nm vertical-cavity surface-emitting lasers with Zn-diffusion and oxide-relief apertures for > 50 Gbit/sec OOK and 4-PAM transmission

Proc. SPIE. 10122, Vertical-Cavity Surface-Emitting Lasers XXI

KEYWORDS: Oxides, Multimode fibers, Transmitters, Light sources, Digital signal processing, Modulation, Dispersion, Resistance, Doping, Signal processing, Photonics, Solids, Measurement devices, Vertical cavity surface emitting lasers, Forward error correction, Optical interconnects

Read Abstract

PROCEEDINGS ARTICLE | February 25, 2017

Continuous wave and modulation performance of 1550nm band wafer-fused VCSELs with MBE-grown InP-based active region and GaAs-based DBRs

Proc. SPIE. 10122, Vertical-Cavity Surface-Emitting Lasers XXI

KEYWORDS: Wafer-level optics, Photodetectors, Eye, Quantum wells, Continuous wave operation, Fiber to the x, Modulation, Aluminum, Vertical cavity surface emitting lasers, Gallium

Read Abstract

PROCEEDINGS ARTICLE | February 25, 2017

Robustness versus thermal effects of single-mode operation of vertical-cavity surface-emitting lasers with engineered leakage of high-order transverse optical modes

Proc. SPIE. 10122, Vertical-Cavity Surface-Emitting Lasers XXI

KEYWORDS: Semiconductors, Oxides, Thermography, Refractive index, Dielectrics, Laser applications, Control systems, 3D modeling, Thermal effects, Distributed Bragg reflectors, Vertical cavity surface emitting lasers, Laser optics, Thermal modeling, Absorption

Read Abstract

PROCEEDINGS ARTICLE | February 22, 2017

Green, yellow and bright red (In,Ga,Al)P–GaP diode lasers grown on high-index GaAs substrates

Proc. SPIE. 10086, High-Power Diode Laser Technology XV

KEYWORDS: Refractive index, Visible radiation, Quantum wells, Waveguides, High power lasers, Electrons, Gallium arsenide, Semiconductor lasers, Diodes, Aluminum, Laser damage threshold, Gallium, Aluminium phosphide

Read Abstract

PROCEEDINGS ARTICLE | February 16, 2017

Resonant cavity light–emitting diodes based on dielectric passive cavity structures

Proc. SPIE. 10124, Light-Emitting Diodes: Materials, Devices, and Applications for Solid State Lighting XXI

KEYWORDS: Semiconductors, Oxides, Refractive index, Multilayers, Light sources, Quantum wells, Light emitting diodes, Etching, Dielectrics, Photonic crystals, Distributed Bragg reflectors, Diodes, Vertical cavity surface emitting lasers, Light

Read Abstract

A novel design for high brightness planar technology light-emitting diodes (LEDs) and LED on-wafer arrays on absorbing substrates is proposed. The design integrates features of passive dielectric cavity deposited on top of an oxide– semiconductor distributed Bragg reflector (DBR), the p–n junction with a light emitting region is introduced into the top semiconductor λ/4 DBR period. A multilayer dielectric structure containing a cavity layer and dielectric DBRs is further processed by etching into a micrometer–scale pattern. An oxide–confined aperture is further amended for current and light confinement. We study the impact of the placement of the active region into the maximum or minimum of the optical field intensity and study an impact of the active region positioning on light extraction efficiency. We also study an etching profile composed of symmetric rings in the etched passive cavity over the light emitting area. The bottom semiconductor is an AlGaAs–AlAs multilayer DBR selectively oxidized with the conversion of the AlAs layers into AlO_x to increase the stopband width preventing the light from entering the semiconductor substrate. The approach allows to achieve very high light extraction efficiency in a narrow vertical angle keeping the reasonable thermal and current conductivity properties. As an example, a micro-LED structure has been modeled with AlGaAs-AlAs or AlGaAs-AlO_x DBRs and an active region based on InGaAlP quantum well(s) emitting in the orange spectral range at ~610 nm. A passive dielectric SiO₂ cavity is confined by dielectric Ta₂O₅/SiO₂ and AlGaAs-AlO_x DBRs. Cylindrically–symmetric structures with multiple ring patterns are modeled. It is demonstrated that the extraction coefficient of light to the air can be increased from 1.3% up to above 90% in a narrow vertical angle (full width at half maximum (FWHM) below 20°). For very small oxide–confined apertures ~100nm the narrowing of the FWHM for light extraction can be reduced down to 5°. Consequently high efficiency high brightness arrays of micro-LEDs becomes possible. For single emitters the approach is particularly interesting for oscillator strength engineering allowing high speed data transmission and for single photonics applying single quantum dot (QD) emitters and allowing >90% coupling of the emission into single mode fiber. We also note that for longer wavelength (~1300nm) QDs the thickness of the layers and surface patterns significantly increase allowing greatly reduced processing tolerances and applying further simplifications due to the possibility of using high contrast GaAs-AlO_x DBRs.

PROCEEDINGS ARTICLE | February 10, 2017

Relative intensity noise of single- and multi-mode 850 nm vertical-cavity surface-emitting lasers

Proc. SPIE. 10325, Optical Fibers and Their Applications 2017

KEYWORDS: Vertical cavity surface emitting lasers

Read Abstract

PROCEEDINGS ARTICLE | February 10, 2017

Impact of the sample modal composition of 850nm VCSELs on high speed data transmission over multimode fiber applying different modulation formats

Proc. SPIE. 10325, Optical Fibers and Their Applications 2017

KEYWORDS: Multimode fibers, Modulation, Data transmission, Vertical cavity surface emitting lasers, Data communications

Read Abstract

PROCEEDINGS ARTICLE | February 10, 2017

High speed 850 nm single mode and multi mode VCSEL transmission over multimode fiber

Proc. SPIE. 10325, Optical Fibers and Their Applications 2017

KEYWORDS: Multimode fibers, Optical fibers, Vertical cavity surface emitting lasers

Read Abstract

SPIE Journal Paper | November 10, 2016

Temperature characteristics of tilted wave lasers

Maximov, Mikhail , Gordeev, Nikita , Shernyakov, Yuri , Payusov, Alexey , Kalyuzhnyy, Nikolay , Mintairov, Sergey , Kulagina, Marina , Zhukov, Alexey , Shchukin, Vitaly , Ledentsov, Nikolai

OE Vol. 55 Issue 11

KEYWORDS: Waveguides, Refractive index, Active optics, Temperature metrology, Quantum wells, Continuous wave operation, Mirrors, Semiconductor lasers, Metalorganic chemical vapor deposition

Read Abstract

PROCEEDINGS ARTICLE | September 28, 2016

On high speed transmission with the 850nm VCSELs

Proc. SPIE. 10031, Photonics Applications in Astronomy, Communications, Industry, and High-Energy Physics Experiments 2016

KEYWORDS: Multimode fibers, Transmitters, Energy efficiency, Switching, Modulation, Power supplies, Optical communications, Vertical cavity surface emitting lasers, Data centers, Data communications

Read Abstract

PROCEEDINGS ARTICLE | March 4, 2016

Close to 100 Gbps discrete multitone transmission over 100m of multimode fiber using a single transverse mode 850nm VCSEL

Proc. SPIE. 9766, Vertical-Cavity Surface-Emitting Lasers XX

KEYWORDS: Oxides, Multimode fibers, Digital signal processing, Modulation, Optical microscopy, Data transmission, Electroluminescence, Vertical cavity surface emitting lasers, Forward error correction, Optical interconnects

Read Abstract

PROCEEDINGS ARTICLE | March 4, 2016

Direct visualization of the in-plane leakage of high-order transverse modes in vertical-cavity surface-emitting lasers mediated by oxide-aperture engineering

Proc. SPIE. 9766, Vertical-Cavity Surface-Emitting Lasers XX

KEYWORDS: Oxides, Data modeling, Modulation, Visualization, Ions, Zinc, Electroluminescence, 3D modeling, CCD cameras, Vertical cavity surface emitting lasers, Neodymium

Read Abstract

PROCEEDINGS ARTICLE | March 4, 2016

Optical mode engineering and high power density per facet length (>8.4 kW/cm) in tilted wave laser diodes

Proc. SPIE. 9733, High-Power Diode Laser Technology and Applications XIV

KEYWORDS: Refractive index, Mirrors, Waveguides, High power lasers, Laser processing, Laser applications, Laser development, Photonic crystals, Semiconductor lasers, Diodes, Optical engineering, Waveguide lasers, Active optics

Read Abstract

PROCEEDINGS ARTICLE | March 4, 2016

Passive cavity surface-emitting lasers: option of temperature-insensitive lasing wavelength for uncooled dense wavelength division multiplexing systems

Proc. SPIE. 9766, Vertical-Cavity Surface-Emitting Lasers XX

KEYWORDS: Semiconductors, Refractive index, Titanium dioxide, Silica, Dielectrics, Reflectivity, Semiconductor lasers, Distributed Bragg reflectors, Vertical cavity surface emitting lasers, Temperature metrology

Read Abstract

PROCEEDINGS ARTICLE | September 11, 2015

Adaptive optical interconnects: the ADDAPT project

Proc. SPIE. 9662, Photonics Applications in Astronomy, Communications, Industry, and High-Energy Physics Experiments 2015

KEYWORDS: Transceivers, Optical components, Clocks, Switching, Modulation, Telecommunications, Optical networks, Data centers, Data communications, Optical interconnects

Read Abstract

PROCEEDINGS ARTICLE | March 20, 2015

Engineering of optical modes in vertical-cavity microresonators by aperture placement: applications to single-mode and near-field lasers

Proc. SPIE. 9381, Vertical-Cavity Surface-Emitting Lasers XIX

KEYWORDS: Semiconductors, Oxides, Refractive index, Waveguides, Resistance, Reflectivity, 3D modeling, Near field, Vertical cavity surface emitting lasers, Near field optics

Read Abstract

PROCEEDINGS ARTICLE | March 16, 2015

Passive cavity laser and tilted wave laser for Bessel-like beam coherently coupled bars and stacks

Proc. SPIE. 9357, Physics and Simulation of Optoelectronic Devices XXIII

KEYWORDS: Refractive index, Gaussian beams, Waveguides, Cladding, Electroluminescence, Semiconductor lasers, Near field, Bessel beams, Near field optics

Read Abstract

PROCEEDINGS ARTICLE | March 9, 2015

850 nm single mode VCSEL-based 25Gx16 transmitter/receiver boards for parallel signal transmission over 1 km of multimode fiber

Proc. SPIE. 9390, Next-Generation Optical Networks for Data Centers and Short-Reach Links II

KEYWORDS: Multimode fibers, Transceivers, Transmitters, Eye, Receivers, Data transmission, Optical fabrication, Vertical cavity surface emitting lasers, Connectors, Optics manufacturing

Read Abstract

PROCEEDINGS ARTICLE | March 9, 2015

Green (In,Ga,Al)P-GaP light-emitting diodes grown on high-index GaAs surfaces

Proc. SPIE. 9383, Light-Emitting Diodes: Materials, Devices, and Applications for Solid State Lighting XIX

KEYWORDS: Light emitting diodes, Aluminium gallium indium phosphide, Cladding, Electrons, Gallium arsenide, Electroluminescence, Transmission electron microscopy, Aluminum, Heterojunctions, Superlattices

Read Abstract

PROCEEDINGS ARTICLE | March 4, 2015

High-speed modulation, wavelength, and mode control in vertical-cavity surface-emitting lasers

Proc. SPIE. 9381, Vertical-Cavity Surface-Emitting Lasers XIX

KEYWORDS: Oxides, Multimode fibers, Optical fibers, Modulation, Dispersion, Dielectrics, Photonic crystals, Near field, Vertical cavity surface emitting lasers, Electro optics

Read Abstract

PROCEEDINGS ARTICLE | March 7, 2014

High differential efficiency tilted wave laser

Proc. SPIE. 8965, High-Power Diode Laser Technology and Applications XII

KEYWORDS: Indium gallium arsenide, Quantum wells, Continuous wave operation, Modulation, Waveguides, Cladding, Indium, Semiconductor lasers, Transmission electron microscopy, Active optics

Read Abstract

PROCEEDINGS ARTICLE | March 13, 2013

Impact of the aperture diameter on the energy efficiency of oxide-confined 850 nm high speed VCSELs

Proc. SPIE. 8639, Vertical-Cavity Surface-Emitting Lasers XVII

KEYWORDS: Oxides, Energy efficiency, Modulation, Quantum efficiency, Resistance, Computing systems, Data transmission, Vertical cavity surface emitting lasers, Optical interconnects, Quantum information

Read Abstract

PROCEEDINGS ARTICLE | May 9, 2012

High-speed VCSELs for energy efficient computer interconnects

Proc. SPIE. 8432, Semiconductor Lasers and Laser Dynamics V

KEYWORDS: Multimode fibers, Optical fibers, Modulation, Data transmission, Vertical cavity surface emitting lasers, Data centers, Optical interconnects, Binary data, Standards development, Temperature metrology

Read Abstract

PROCEEDINGS ARTICLE | February 29, 2012

Passive cavity surface-emitting and edge-emitting lasers: physics, design, modeling

Proc. SPIE. 8255, Physics and Simulation of Optoelectronic Devices XX

KEYWORDS: Waveguides, Cladding, Dielectrics, Laser scattering, Reflectivity, Semiconductor lasers, Laser cutting, Vertical cavity surface emitting lasers, Active optics, Phase shifts

Read Abstract

PROCEEDINGS ARTICLE | February 7, 2012

Progress on single mode VCSELs for data- and tele-communications

Proc. SPIE. 8276, Vertical-Cavity Surface-Emitting Lasers XVI

KEYWORDS: Oxides, Multimode fibers, Modulation, Reliability, Data transmission, Vertical cavity surface emitting lasers, Data communications, Optical interconnects, Standards development, Temperature metrology

Read Abstract

PROCEEDINGS ARTICLE | February 7, 2012

Multi-mode to single-mode switching caused by self-heating in bottom-emitting intra-cavity contacted 960 nm VCSELs

Proc. SPIE. 8276, Vertical-Cavity Surface-Emitting Lasers XVI

KEYWORDS: Oxides, Quantum wells, Switching, Waveguides, Metals, Vertical cavity surface emitting lasers, Convection, Optical microcavities, Near field optics

Read Abstract

PROCEEDINGS ARTICLE | February 7, 2012

Energy-efficient vertical-cavity surface-emitting lasers (VCSELs) for "green" data and computer communication

Proc. SPIE. 8276, Vertical-Cavity Surface-Emitting Lasers XVI

KEYWORDS: Multimode fibers, Optical fibers, Energy efficiency, Modulation, Data transmission, Vertical cavity surface emitting lasers, Data communications, Optical interconnects, Semiconducting wafers, Temperature metrology

Read Abstract

PROCEEDINGS ARTICLE | November 28, 2011

High-speed 850 and 980 nm VCSELs for high-performance computing applications

Proc. SPIE. 8308, Optoelectronic Materials and Devices VI

KEYWORDS: Oxides, Multimode fibers, Light sources, Quantum wells, Gallium arsenide, Data transmission, Vertical cavity surface emitting lasers, Optical interconnects, Binary data, Temperature metrology

Read Abstract

PROCEEDINGS ARTICLE | November 28, 2011

850 nm optical components for 25 Gb/s optical fiber data communication links over 100 m at 85°C

Proc. SPIE. 8308, Optoelectronic Materials and Devices VI

KEYWORDS: Oxides, Multimode fibers, Optical fibers, Eye, Modulation, Capacitance, Palladium, Vertical cavity surface emitting lasers, Fiber optic communications, Data communications

Read Abstract

PROCEEDINGS ARTICLE | February 21, 2011

Analogue modulation performance of 20 GHz vertical cavity surface emitting lasers for radio over fiber applications

Proc. SPIE. 7933, Physics and Simulation of Optoelectronic Devices XIX

KEYWORDS: Oxides, Refractive index, Radio optics, Modulation, Radio over Fiber, Vertical cavity surface emitting lasers, Electro optics, Data communications, Analog modulation, Hybrid fiber radio

Read Abstract

PROCEEDINGS ARTICLE | February 8, 2011

High-speed single-mode quantum dot and quantum well VCSELs

Proc. SPIE. 7952, Vertical-Cavity Surface-Emitting Lasers XV

KEYWORDS: Oxides, Multimode fibers, Optical fibers, Eye, Quantum wells, Modulation, Luminescence, Receivers, Quantum dots, Vertical cavity surface emitting lasers

Read Abstract

PROCEEDINGS ARTICLE | April 28, 2010

Oxide confined 850-nm VCSELs for high-speed datacom applications

Proc. SPIE. 7720, Semiconductor Lasers and Laser Dynamics IV

KEYWORDS: Oxides, Signal to noise ratio, Photodetectors, Eye, Modulation, Reliability, Data transmission, Picosecond phenomena, Vertical cavity surface emitting lasers, Data communications

Read Abstract

PROCEEDINGS ARTICLE | February 26, 2010

Optical components for very short reach applications at 40 Gb/s and beyond

Proc. SPIE. 7597, Physics and Simulation of Optoelectronic Devices XVIII

KEYWORDS: Oxides, Optical components, Modulation, Image processing, Copper, Reliability, Electroluminescence, Integrated circuits, Vertical cavity surface emitting lasers, Standards development

Read Abstract

PROCEEDINGS ARTICLE | February 26, 2010

Modeling of photonic-crystal-based high-power high-brightness semiconductor lasers

Proc. SPIE. 7597, Physics and Simulation of Optoelectronic Devices XVIII

KEYWORDS: Waveguides, Cladding, High power lasers, Crystals, Photonic crystals, Semiconductor lasers, Near field, Phase matching, Active optics, Near field optics

Read Abstract

PROCEEDINGS ARTICLE | February 12, 2010

High-power high-brightness semiconductor lasers based on novel waveguide concepts

Proc. SPIE. 7616, Novel In-Plane Semiconductor Lasers IX

KEYWORDS: Refractive index, Continuous wave operation, Waveguides, Cladding, High power lasers, Photonic crystals, Semiconductor lasers, Laser crystals, Waveguide lasers

Read Abstract

PROCEEDINGS ARTICLE | February 6, 2010

High-speed 850 nm oxide-confined VCSELs for DATACOM applications

Proc. SPIE. 7615, Vertical-Cavity Surface-Emitting Lasers XIV

KEYWORDS: Oxides, Signal to noise ratio, Optical fibers, Eye, Modulation, Reliability, Resistance, Computing systems, Vertical cavity surface emitting lasers, Data communications

Read Abstract

PROCEEDINGS ARTICLE | February 24, 2009

20 Gbit/s error free transmission with ~850 nm GaAs-based vertical cavity surface emitting lasers (VCSELs) containing InAs-GaAs submonolayer quantum dot insertions

Proc. SPIE. 7211, Physics and Simulation of Optoelectronic Devices XVII

KEYWORDS: Indium gallium arsenide, Quantum wells, Indium arsenide, Modulation, Gallium arsenide, Quantum dots, Telecommunications, Vertical cavity surface emitting lasers, Semiconducting wafers, Optical microcavities

Read Abstract

PROCEEDINGS ARTICLE | February 18, 2009

Quantum dot insertions in VCSELs from 840 to 1300 nm: growth, characterization, and device performance

Proc. SPIE. 7224, Quantum Dots, Particles, and Nanoclusters VI

KEYWORDS: Multimode fibers, Eye, Indium arsenide, Modulation, Copper, Quantum dots, Transmission electron microscopy, Vertical cavity surface emitting lasers, Frequency conversion

Read Abstract

PROCEEDINGS ARTICLE | February 7, 2009

120°C 20 Gbit/s operation of 980nm VCSEL based on sub-monolayer growth

Proc. SPIE. 7229, Vertical-Cavity Surface-Emitting Lasers XIII

KEYWORDS: Oxides, Indium gallium arsenide, Quantum wells, Modulation, Resistance, Semiconductor lasers, Signal analysis, Vertical cavity surface emitting lasers, Detection theory, Temperature metrology

Read Abstract

PROCEEDINGS ARTICLE | November 18, 2008

Tilted cavity concept for the high-power wavelength stabilized diode lasers

Proc. SPIE. 7138, Photonics, Devices, and Systems IV

KEYWORDS: Continuous wave operation, Modulation, High power lasers, Gallium arsenide, Reflectivity, Semiconductor lasers, Laser stabilization, Vertical cavity surface emitting lasers, Pulsed laser operation, Temperature metrology

Read Abstract

PROCEEDINGS ARTICLE | April 25, 2008

Energy characteristics of excitons in InGaN/GaN heterostructures

Proc. SPIE. 6995, Optical Micro- and Nanometrology in Microsystems Technology II

KEYWORDS: Quantum wells, Light emitting diodes, Optical properties, Ultraviolet radiation, Luminescence, Indium, Gallium nitride, Excitons, Indium gallium nitride, Heterojunctions

Read Abstract

PROCEEDINGS ARTICLE | March 5, 2008

Quantum dot photonics: edge emitter amplifier, and VCSEL

Proc. SPIE. 7009, Second International Conference on Advanced Optoelectronics and Lasers

KEYWORDS: Eye, Indium gallium arsenide, Modulation, Mode locking, Quantum dots, Semiconductor lasers, Picosecond phenomena, Vertical cavity surface emitting lasers, Pulsed laser operation

Read Abstract

PROCEEDINGS ARTICLE | February 22, 2008

High-power one-, two-, and three-dimensional photonic crystal edge-emitting laser diodes for ultra-high brightness applications

Proc. SPIE. 6889, Physics and Simulation of Optoelectronic Devices XVI

KEYWORDS: Refractive index, Continuous wave operation, Waveguides, High power lasers, Laser applications, Photonic crystals, Semiconductor lasers, Laser crystals, Pulsed laser operation, Near field optics

Read Abstract

PROCEEDINGS ARTICLE | February 22, 2008

Ultra high-speed electro-optically modulated VCSELs: modeling and experimental results

Proc. SPIE. 6889, Physics and Simulation of Optoelectronic Devices XVI

KEYWORDS: Refractive index, Mirrors, Quantum wells, Modulation, Reflectivity, Modulators, Excitons, Vertical cavity surface emitting lasers, Electro optics, Absorption

Read Abstract

PROCEEDINGS ARTICLE | February 7, 2007

Novel concepts for ultrahigh-speed quantum-dot VCSELs and edge-emitters

Proc. SPIE. 6468, Physics and Simulation of Optoelectronic Devices XV

KEYWORDS: Refractive index, Continuous wave operation, Indium arsenide, Modulation, Gallium arsenide, Modulators, Transmission electron microscopy, Vertical cavity surface emitting lasers, Electro optics

Read Abstract

PROCEEDINGS ARTICLE | July 12, 2006

High brilliance photonic band crystal lasers

Proc. SPIE. 6350, Workshop on Optical Components for Broadband Communication

KEYWORDS: Refractive index, Waveguides, High power lasers, Crystals, Gallium arsenide, Reflectivity, Photonic crystals, Semiconductor lasers, Laser crystals, Near field optics

Read Abstract

High concentration of optical power in a narrow exit angle is extremely important for numerous applications of laser diodes, for example, for low-cost fiber pumping and coupling, material processing, direct frequency conversion, etc. Lasers based on the longitudinal photonic band crystal (PBC) concept allow a robust and controllable extension of the fundamental mode over a thick multi-layer waveguide region to achieve a very large vertical optical mode spot size and, consequently, a very narrow vertical beam divergence. Many undesirable effects like beam filamentation, lateral multimode operation and catastrophic optical mirror damage (COMD) are strongly reduced. 650 nm GaInP/GaAlInP PBC lasers show narrow far field pattern (FWHM~7°) stable up to the highest output powers. Differential efficiency up to 85% is demonstrated. Total single mode output power as high as 150 mW is achieved in 4 μm-wide stripes in continuous wave operation, being limited by COMD due to not passivated facets. The lateral far field FWHM is 4 degrees. 840 nm GaAs/GaAlAs PBC lasers show a vertical beam divergence of 8° (FWHM) and a high differential efficiency up to 95% (L=500 μm). A total single mode CW power approaches 500 mW for 1 mm-long 4 μm-wide stripes devices at ~500 mA current, being COMD-limited. The lateral far field FWHM is 5 degrees. Another realization of a longitudinal PBC laser allows lasing in a single high-order vertical mode, a so-called tilted mode, which provides wavelength selectivity and substantially extends the possibility to control the thermal shift of the lasing wavelength. In a multilayer laser structure, where the refractive index of each layer increases upon temperature, it is possible to reach both a red shift of the lasing wavelength for some realizations of the structures, and a blue shift for some others. Most important, the absolute thermal stabilization of the lasing wavelength of a semiconductor laser can be realized.

PROCEEDINGS ARTICLE | July 6, 2006

Self organized quantum dots for 1.3 µm photonic devices

Proc. SPIE. 6350, Workshop on Optical Components for Broadband Communication

KEYWORDS: Ultrafast phenomena, Eye, Optical amplifiers, Modulation, Mode locking, Quantum dots, Semiconductor lasers, Picosecond phenomena, Laser optics, Pulsed laser operation

Read Abstract

PROCEEDINGS ARTICLE | July 6, 2006

20-Gb/s direct modulation of 980 nm VCSELs based on submonolayer deposition of quantum dots

Proc. SPIE. 6350, Workshop on Optical Components for Broadband Communication

KEYWORDS: Eye, Indium gallium arsenide, Quantum wells, Indium arsenide, Modulation, Gallium arsenide, Quantum dots, Transmission electron microscopy, Vertical cavity surface emitting lasers, Gallium

Read Abstract

PROCEEDINGS ARTICLE | June 13, 2006

Semiconductor quantum dot lasers

Proc. SPIE. 5946, Optical Materials and Applications

Read Abstract

PROCEEDINGS ARTICLE | June 13, 2006

Epitaxial growth of quantum-dot heterostructures on metamorphic buffers

Proc. SPIE. 5946, Optical Materials and Applications

Read Abstract

PROCEEDINGS ARTICLE | February 28, 2006

Longitudinal photonic bandgap crystal laser diodes with ultra-narrow vertical beam divergence

Proc. SPIE. 6115, Physics and Simulation of Optoelectronic Devices XIV

KEYWORDS: Refractive index, Light emitting diodes, Waveguides, Cladding, Crystals, Photonic crystals, Semiconductor lasers, Laser crystals, Geometrical optics, Near field optics

Read Abstract

PROCEEDINGS ARTICLE | February 22, 2006

1.3-1.5 µm quantum dot lasers on foreign substrates: growth using defect reduction technique, high-power CW operation, and degradation resistance

Proc. SPIE. 6133, Novel In-Plane Semiconductor Lasers V

KEYWORDS: Indium gallium arsenide, Quantum wells, Continuous wave operation, Indium arsenide, High power lasers, Gallium arsenide, Quantum dots, Semiconductor lasers, Laser stabilization

Read Abstract

We have performed a systematic study of structural and optical properties of Quantum dot (QDs) lasers based on InAs/InGaAs quantum dots grown on GaAs substrates emitting in the 1.3 - 1.5 μm range. 1.3 μm range QD lasers are grown using GaAs as matrix material. It is shown that the lasers, grown with large number of QD stacks are metamorphic, with plastic relaxation occurring through the formation of misfit dislocations. Thus, 1.3 μm QD lasers with large number of stacks grown without strain compensation are metamorphic. Another type of defects is related to local dislocated clusters, which are the most dangerous. When proper optimization of the growth conditions is carried out, including a selective thermal etching off of statistically formed dislocated clusters through the defect-reduction technique (DRT), no significant impact of misfit dislocations on the degradation robustness is observed. In uncoated devices a high cw single mode power of ~700 mW is realized limited by thermal roll-over, which is not affected by 500 h ageing at room temperature. At elevated temperatures the main degradation mechanism revealed is catastrophic optical mirror damage (COMD). When the facet are passivated, the devices show the extrapolated operation lifetime in excess of 10⁶ h at 40°C at ~100 mW cw single mode output power. Longer wavelength (1.4 - 1.5 μm) devices are grown on metamorphic (In,Ga,Al)As layers deposited on GaAs substrates. In this case, the plastic relaxation occurs through formation of both misfit and threading dislocations. The latter kill the device performance. Using DRT in this case enables blocking of threading dislocation with growth of QDs in defect-free upper layers. DRT is realized by selective capping of the defect-free areas and high-temperature etching of nano-holes at the non-capped regions near the dislocation. The procedure results in etching of holes and is followed by fast lateral overgrowth with merger of the growth fronts. If the defect does not propagate into the upper layer when the hole is capped, the upper layers become defect-free. Lasers based on this approach exhibited emission wavelength in the 1.4 -1.5 μm range with a differential quantum efficiency of about ~50%. The narrow-stripe lasers operate in a single transverse mode and withstand continuous current density above 20 kA cm^-2 without degradation. A maximum continuous-wave output power of 220 mW limited by thermal roll-over is obtained. No beam filamentation was observed up to the highest pumping levels. Narrow stripe devices with as-cleaved facets are tested for 60°C (800 h) and 70°C (200 h) on-chip temperature. No noticeable degradation has been observed at 50 mW cw single mode output power. This shows the possibility of degradation-robust devices on foreign substrates. The technology opens a way for integration of various III-V materials and may target degradation-free lasers on silicon for further convergence of computing and communications.

PROCEEDINGS ARTICLE | April 28, 2005

Edge and surface-emitting tilted cavity lasers

Proc. SPIE. 5722, Physics and Simulation of Optoelectronic Devices XIII

KEYWORDS: Refractive index, Quantum wells, Waveguides, Reflection, Gallium arsenide, Reflectivity, Electroluminescence, Semiconductor lasers, Near field, Vertical cavity surface emitting lasers

Read Abstract

PROCEEDINGS ARTICLE | April 28, 2005

Temperature dependent output characteristics of p-doped 1.1 and 1.3 µm quantum dot lasers

Proc. SPIE. 5722, Physics and Simulation of Optoelectronic Devices XIII

KEYWORDS: Modulation, Electrons, Gallium arsenide, Quantum dots, Measurement devices, Laser damage threshold, Gallium, Heterojunctions, Quantum dot lasers, Temperature metrology

Read Abstract

PROCEEDINGS ARTICLE | January 31, 2005

QD lasers: physics and applications

Proc. SPIE. 5624, Semiconductor and Organic Optoelectronic Materials and Devices

KEYWORDS: Indium gallium arsenide, Indium arsenide, Annealing, Gallium arsenide, Quantum dots, Semiconductor lasers, Transmission electron microscopy, Laser stabilization, Vertical cavity surface emitting lasers, Heterojunctions

Read Abstract

PROCEEDINGS ARTICLE | September 1, 2004

Mode locking of InGaAs quantum dot lasers

Proc. SPIE. 5452, Semiconductor Lasers and Laser Dynamics

KEYWORDS: Waveguides, Etching, Mode locking, Fourier transforms, Quantum dots, Semiconductor lasers, Oscilloscopes, Gallium, Pulsed laser operation, Quantum dot lasers

Read Abstract

PROCEEDINGS ARTICLE | August 2, 2004

Tilted cavity laser (Critical Review Lecture)

Proc. SPIE. 5509, Nanomodeling

KEYWORDS: Reflectors, Refractive index, Quantum wells, Gallium arsenide, Reflectivity, Electroluminescence, Quantum dots, Semiconductor lasers, Laser stabilization, Temperature metrology

Read Abstract

PROCEEDINGS ARTICLE | June 18, 2004

Long-wavelength (1.3-1.5 micron) quantum dot lasers based on GaAs

Proc. SPIE. 5349, Physics and Simulation of Optoelectronic Devices XII

KEYWORDS: Quantum wells, Continuous wave operation, Mode locking, Gallium arsenide, Laser applications, Semiconductor lasers, Diodes, Laser damage threshold, Vertical cavity surface emitting lasers, Gallium

Read Abstract

PROCEEDINGS ARTICLE | May 11, 2004

High-power ultra-fast single- and multi-mode quantum dot lasers with superior beam profile

Proc. SPIE. 5365, Novel In-Plane Semiconductor Lasers III

KEYWORDS: Quantum wells, Modulation, Waveguides, Cladding, Mode locking, Gallium arsenide, Semiconductor lasers, Diodes, Laser damage threshold, Gallium

Read Abstract

PROCEEDINGS ARTICLE | May 11, 2004

Mode-locked quantum dot lasers for picosecond pulse generation

Proc. SPIE. 5365, Novel In-Plane Semiconductor Lasers III

KEYWORDS: Spectrum analysis, Etching, Mode locking, Quantum dots, Semiconductor lasers, Picosecond phenomena, Oscilloscopes, Gallium, Pulsed laser operation, Quantum dot lasers

Read Abstract

PROCEEDINGS ARTICLE | July 25, 2003

Recent advances in long-wavelength GaAs-based quantum dot lasers

Proc. SPIE. 4986, Physics and Simulation of Optoelectronic Devices XI

KEYWORDS: Semiconductors, Quantum wells, Indium arsenide, Gallium arsenide, Quantum dots, Semiconductor lasers, Vertical cavity surface emitting lasers, Gallium, Quantum dot lasers

Read Abstract

PROCEEDINGS ARTICLE | July 1, 2003

High-performance of single mode InAs/InGaAs/GaAs quantum dot lasers of 1.3-micron range

Proc. SPIE. 4999, Quantum Sensing: Evolution and Revolution from Past to Future

KEYWORDS: Indium gallium arsenide, Continuous wave operation, Indium arsenide, Gallium arsenide, Laser applications, Semiconductor lasers, Laser damage threshold, Vertical cavity surface emitting lasers, Gallium, Temperature metrology

Read Abstract