A5037843786- Advanced Fiber Laser Technologies
- Photonic Crystal and Fiber Optics
- Advanced Fiber Optic Sensors
- Space Satellite Systems and Control
- Optical Network Technologies
- Spacecraft Design and Technology
- Laser-Matter Interactions and Applications
- Spectroscopy and Laser Applications
- Dynamics and Control of Mechanical Systems
- Astro and Planetary Science
- Astronomy and Astrophysical Research
- Semiconductor Lasers and Optical Devices
- Rocket and propulsion systems research
- Photonic and Optical Devices
- Atmospheric and Environmental Gas Dynamics
- Solid State Laser Technologies
- Stellar, planetary, and galactic studies
- Laser Design and Applications
- Control and Dynamics of Mobile Robots
- Stability and Control of Uncertain Systems
- Advanced Control Systems Optimization
- Experimental and Theoretical Physics Studies
- Adaptive Control of Nonlinear Systems
- Structural Analysis and Optimization
- Human-Automation Interaction and Safety
KTH Royal Institute of Technology
2015-2022
University of Virginia
2013-2018
European Space Research and Technology Centre
2006-2010
National Institute of Aerospace
2008-2009
Langley Research Center
2008
Naval Postgraduate School
2006
Naval Air Systems Command
2006
Orbital Systems (Sweden)
1997
Orbital ATK (United States)
1989-1993
United States Naval Research Laboratory
1981-1986
Abstract In this work, we show that the nonlinear evolution of femtosecond seed pulses with different parameters (temporal and spectral shapes, repetition rate, pulse energy) in an Yb-fiber amplifier leads to gain-managed amplification, enabling robust generation high-peak-power nearly transform-limited after external compression. We demonstrate a compressed duration 33 fs energy 80.5 nJ peak power 2.29 MW for source rate 30 MHz. For second 125 MHz, obtained 51 22.8 420 kW. Numerical...
A new formulation of independent modal space control is developed to handle the attitude and shape problem for large flexible spacecraft. The main advantage this method that one can obtain an analytical solution optimal law very high dimensional systems. fundamental limitation previous work—the requirement actuator each mode be controlled—is relaxed in formulation. closed-loop design obtained while independently assuring stability may iterated improve performance. process shown simple...
Abstract A numerical model for amplification of ultrashort pulses with high repetition rates in fiber amplifiers is presented. The pulse propagation modeled by jointly solving the steady-state rate equations and generalized nonlinear Schrödinger equation, which allows accurate treatment dispersive effects whilst considering arbitrary spatial spectral gain dependencies. Comparison data acquired using developed experimental results prove to be good agreement.
A molecular laser-radar system, based on the Scheimpflug principle, has been constructed and demonstrated for remote sensing of atmospheric CO2 concentrations using Differential Absorption Lidar (DIAL) in (30012←00001) absorption band. The laser source is a Continues Wave (CW) Distributed-FeedBack (DFB) diode seeding an Erbium-doped fiber amplifier, emitting narrowband (3 MHz) tunable radiation with output power 1.3 W at 1.57 µm. beam expanded transmitted to atmosphere. backscattered signal...
We present the performance of an all polarization-maintaining Erbium-doped fiber laser mode-locked by a multilayer graphene based saturable absorber. The cavity incorporates Martinez-type compressor, on transmission grating, which allows for continuous tuning net dispersion as well spectral filtering. By adjusting and bandwidth, we could operate in soliton, managed soliton absorber-limited pulse regimes. durations from ranged between 338 fs to 2.1 ps be operated at nearly constant output...
We describe a simple, narrow-linewidth, tunable fiber-based laser with high degree of tuning accuracy. A polarization independent semiconductor optical amplifier (SOA) is used as the gain medium in unidirectional fiber ring cavity circulator connected to 6-meter long chirped Bragg grating (CFBG). The wavelength chosen by setting modulation frequency SOA same harmonics fundamental repetition rate light reflected at specific point on CFBG. Careful management drive current and pulse width helps...
Ultrafast sources in the mid-IR are indispensable research tools for spectroscopic and medical applications can also potentially be used to generate attosecond pulses. We investigated a route t ...
In this paper, we report an all-fiber supercontinuum source pumped with ultra-short pulses at 1.9–2.0 μm, covering over octave (1200–2400 nm). We investigated the shot-to-shot stability of generated in a commercially available highly nonlinear fiber (HNLF) different lengths, ranging from 5 to 80 cm, by employing dispersive Fourier transform method. Our study shows that using shorter HNLFs significantly improves while maintaining broad spectral...
The incorporation of Hypersonic Inflatable Aerodynamic Decelerator (HIAD) technology into entry vehicle designs opens up a new avenue for trajectory control through shape morphing the inflatable structure. In this work, we explore effects utilizing super ellipse model aeroshell generation, Modified Newtonian Impact Theory aerodynamic evaluation, three degree-of-freedom (3 DOF) simulation, and stagnation point heating to evaluate morphed shapes their effect on trajectory. Reentry Vehicle...
We present an efficient fiber source designed for continuous-wave differential absorption light detection and ranging (CW DIAL) of atmospheric CO2-concentration. It has a linewidth 3 MHz, tuning range 2 nm over the CO2 peaks at 1.572 µm, output power 1.3 W limited by available pump power. Results from initial CW DIAL testing are also presented discussed.
For the purpose of selecting actuator locations for control systems such as large flexible spacecraft, a concept degree controllability has recently been developed. The exact value cannot, in general, be determined closed form. In this work, it is shown that lower bound estimate can easily by discretizing continuous system to obtain an approximation recovery region. A computational procedure developed characterize approximate region and determine minimum distance boundary Examples are...
In this work, we explore the interrogation of an array fiber Bragg gratings as part a laser cavity. A semiconductor optical amplifier in sigma-shaped cavity provides gain and is gated periodically at rate that matches roundtrip time associated with each grating array. The interrogator exhibits clear properties such threshold linewidth narrowing. Besides improving signal-to-noise ratio enabling re-use wavelengths, it found scheme enables monitoring weak spaced by less than 1 cm. Intracavity...
We present a novel C-cavity concept for tunable lasers. The laser is based on semiconductor optical amplifier (SOA), serving both as gain medium well modulator, and chirped fiber Bragg grating (C-FBG) which acts the end mirrors cavity ends. Driving SOA with pulse pair variable delay enables wavelength tuning by targeting different regions in C-FBG circulating pulse. design allows wide while maintaining constant repetition rate, we show range of 35 nm -limited C-FBG's reflection bandwidth....
A high school district has developed an in‐service counselor education program for minority teachers to help meet its need more counselors who, by virtue of skin color, language, or inner city origins, have advantages in relating students. One major component the is counseling practicum which are supervised while they work with
Predictions of Total Ionizing Dose made using full 3-D Monte Carlo and simplified sector-shielding techniques for simple complex geometries in a space environment are compared differences between them analyzed detail
Cas d'un robot manipulateur monte sur un satellite. Etude cinematique et compensation des moments de reaction