Jan E. Kansky
Massachusetts Institute of Technology
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Featured researches published by Jan E. Kansky.
Optics Letters | 2011
Shawn Redmond; Kevin Creedon; Jan E. Kansky; Steven J. Augst; Leo J. Missaggia; Michael K. Connors; Robin K. Huang; Bien Chann; Tso Yee Fan; George W. Turner; Antonio Sanchez-Rubio
We have demonstrated active coherent beam combination (CBC) of up to 218 semiconductor amplifiers with 38.5 W cw output using up to eleven one-dimensional 21-element individually addressable diode amplifier arrays operating at 960 nm. The amplifier array elements are slab-coupled-optical-waveguide semiconductor amplifiers (SCOWAs) set up in a master-oscillator-power-amplifier configuration. Diffractive optical elements divide the master-oscillator beam to seed multiple arrays of SCOWAs. A SCOWA was phase actuated by adjusting the drive current to each element and controlled using a stochastic-parallel-gradient-descent (SPGD) algorithm for the active CBC. The SPGD is a hill-climbing algorithm that maximizes on-axis intensity in the far field, providing phase locking without needing a reference beam.
Optics Express | 2009
Benjamin G. Lee; Jan E. Kansky; Anish K. Goyal; Christian Pflügl; Laurent Diehl; Mikhail A. Belkin; A. Sanchez; Federico Capasso
Wavelength beam combining was used to co-propagate beams from 28 elements in an array of distributed-feedback quantum cascade lasers (DFB-QCLs). The beam-quality product of the array, defined as the product of near-field spot size and far-field divergence for the entire array, was improved by a factor of 21 by using wavelength beam combining. To demonstrate the applicability of wavelength beam combined DFB-QCL arrays for remote sensing, we obtained the absorption spectrum of isopropanol at a distance of 6 m from the laser array.
Proceedings of SPIE | 2006
Jan E. Kansky; C. X. Yu; Daniel V. Murphy; Scot E. J. Shaw; R. Lawrence; Charles Higgs
We demonstrate, for the first time to our knowledge, successful beam control of a fiber optic phased array containing a large number of polarization maintaining fibers. As many as forty-eight fibers have been coherently combined via individual all-fiber phase modulators. The residual phase error is less than 1/30th of a wave. Results with both near-field interferometric control and target-in-the-loop control have been obtained. Experimental results are compared with numerical simulations and excellent agreement has been achieved. We investigated propagation of this phased array output through a turbulent atmosphere, and used the all-fiber phase modulators for the compensation of turbulence effects on the array output. This work paves the way towards scaling such fiber optic phased arrays to very high fiber count. Eventually thousand of fibers can be controlled via such a scheme.
Proceedings of SPIE | 2014
Daniel V. Murphy; Jan E. Kansky; Matthew E. Grein; Robert T. Schulein; Matthew M. Willis; Robert E. Lafon
The Lunar Lasercom Ground Terminal (LLGT) is the primary ground terminal for NASA’s Lunar Laser Communication Demonstration (LLCD), which demonstrated for the first time high-rate duplex laser communication between Earth and satellite in orbit around the Moon. The LLGT employed a novel architecture featuring an array of telescopes and employed several novel technologies including a custom PM multimode fiber and high-performance cryogenic photon-counting detector arrays. An overview of the LLGT is presented along with selected results from the recently concluded LLCD.
Optics Letters | 2012
Kevin Creedon; Shawn Redmond; Gary M. Smith; Leo J. Missaggia; Michael K. Connors; Jan E. Kansky; Tso Yee Fan; George W. Turner; Antonio Sanchez-Rubio
We demonstrate 40 W coherently combined output power in a single diffraction-limited beam from a one-dimensional 47-element array of angled-facet slab-coupled optical waveguide amplifiers at 1064 nm. The output from each emitter was collimated and overlapped onto a diffractive optical element combiner using a common transform lens. Phase locking was achieved via active feedback on each amplifiers drive current to maximize the power in the combined beam. The combining efficiency at all current levels was nearly constant at 87%.
Applied Optics | 2012
Juan Montoya; Steven J. Augst; Kevin Creedon; Jan E. Kansky; Tso Yee Fan; Antonio Sanchez-Rubio
Active coherent beam combining of laser oscillators is an attractive way to achieve high output power in a diffraction limited beam. Here we describe an active beam combining system used to coherently combine 21 semiconductor laser elements with an 81% beam combining efficiency in an external cavity configuration compared with an upper limit of 90% efficiency in the particular configuration of the experiment. Our beam combining system utilizes a stochastic parallel gradient descent (SPGD) algorithm for active phase control. This work demonstrates that active beam combining is not subject to the scaling limits imposed on passive-phasing systems.
Optics Express | 2012
W. Ronny Huang; Juan Montoya; Jan E. Kansky; Shawn Redmond; George W. Turner; Antonio Sanchez-Rubio
Beam steering at high speed and high power is demonstrated from a 6-element optical phased array using coherent beam combining (CBC) techniques. The steering speed, defined as the inverse of the time to required to sweep the beam across the steering range, is 40 MHz and the total power is 396 mW. The measured central lobe FWHM width is 565 μrad. High on-axis intensity is maintained periodically by phase-locking the array via a stochastic-parallel-gradient-descent (SPGD) algorithm. A master-oscillator-power-amplifier (MOPA) configuration is used where the amplifier array elements are semiconductor slab-coupled-optical-waveguide-amplifiers (SCOWAs). The beam steering is achieved by LiNbO(3) phase modulators; the phase-locking occurs by current adjustment of the SCOWAs. The system can be readily scaled to GHz steering speed and multiwatt-class output.
SpaceOps 2014 Conference | 2014
Bryan S. Robinson; Don M. Boroson; Dennis A. Burianek; Daniel V. Murphy; Farzana I. Khatri; Abhijit Biswas; Zoran Sodnik; Jamie W. Burnside; Jan E. Kansky; Don M. Cornwell
The Lunar Laser Communication Demonstration (LLCD) is NASA’s first demonstration of the use of free-space optical communications for high-rate duplex communications between a lunar spacecraft and an Earth ground station. The LLCD system comprised a space terminal on the Lunar Atmosphere and Dust Environment Exploration (LADEE) spacecraft and three ground terminals developed by NASA and the European Space Agency. The primary mission occurred during the fall of 2013 and successfully demonstrated reliable data delivery over optical data links operating at rates as high as 20 Mbps on the uplink and 622 Mbps on the downlink.
Proceedings of SPIE | 1998
Charles Higgs; Herbert T. Barclay; Jan E. Kansky; Daniel V. Murphy; Charles A. Primmerman
We have conducted atmospheric compensation experiments using active illumination for both adaptive-optics and tracking. Tests were performed in support of the Air Forces Airborne Laser program. The tests utilized the 5.4-km horizontal propagation range at the Lincoln Laboratory Firepond facility. The adaptive-optics beacon was provided by actively illuminating the target with a multibeam laser illuminator. A second multibeam laser illuminator was used to provide a beacon for an imaging tracker. Experiments were conducted using two different adaptive-optics illuminator configurations, as well as with point-source beacons. Data were collected over a range of atmospheric conditions. Results from these tests have helped to provide a performance benchmark for the Airborne Laser program.
Proceedings of SPIE | 2007
Jan E. Kansky; Daniel V. Murphy
Systems utilizing target-in-the-loop (TIL) techniques for adaptive optics phase compensation rely on a metric sensor to perform a hill climbing algorithm that maximizes the far-field Strehl ratio. In uncooperative TIL, the metric signal is derived from the light backscattered from a target. In cases where the target is illuminated with a laser with suffciently long coherence length, the potential exists for the validity of the metric sensor to be compromised by speckle-field effects. We report experimental results from a scaled laboratory designed to evaluate TIL performance in atmospheric turbulence and thermal blooming conditions where the metric sensors are influenced by varying degrees of backscatter speckle. We compare performance of several TIL configurations and metrics for cases with static speckle, and for cases with speckle fluctuations within the frequency range that the TIL system operates. The roles of metric sensor filtering and system bandwidth are discussed.