| An Octave Bandwidth, High PAE, Linear, Class J GaN High Power Amplifier |
12 Mar 2012 |
6 pages |
| Authors:
Kris Skowronski; Steve Nelson; Rajesh Mongia; Howard Sheehan; Sid Anderson; COBHAM RICHARDSON TX SENSOR SYSTEMS
|
 | In this paper, the design and measured performance of a wideband (1.2-2.5 GHz), high efficiency, high linearity, Gallium Nitride (GaN), Class J, 200-W power amplifier (PA) is reported. The Class J PA output stages exhibit 45-62% power-added efficiency (PAE) and a near-maximum power match over 2:1 bandwidth, and impressive 802.11g WLAN linearity. This linear PA has 65 to 70-dB small-signal gain over this bandwidth. |
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| A Smart Microwave Vacuum Electron Device (MVED) Using Field Emitters |
31 Jan 2012 |
41 pages |
| Authors:
Jim Browning; Sin M Loo; John Chiasson; BOISE STATE UNIV ID DEPT OF ELECTRICAL AND COMPUTER ENGINEERING
|
| A Crossed-Field Amplifier and related components were designed and tested. The device did not show gain. The inability to achieve gain is believed to be related to two causes: insufficient beam current and backward wave modes from the slow wave circuit. ICEPIC modeling of the device showed issues with backward waves, but modifications to the circuit design and CFA operating parameters did not change performance. The field emission arrays intended ... |
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| On-chip Electrical Soliton Oscillators for Picosecond Pulse Self-Generation and THz Electronics |
17 Jan 2012 |
12 pages |
| Authors:
Donhee Ham; HARVARD UNIV CAMBRIDGE MA
|
| Solitons are pulsed waves exhibiting unique nonlinear properties. In electronics domain, electrical solitons had been passively produced by using nonlinear transmission lines. Prior to this proposal, our group built, for the first time, an active electrical circuit in a discrete platform, which robustly self-generated a stable, periodic train of electrical solitons. This was achieved by combining a nonlinear transmission line with a specially designed amplifier in a circular topology. The ... |
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| Leading Edge. Volume 7, Issue Number 4, 2012 |
Jan 2012 |
103 pages |
| Authors:
NAVAL SURFACE WARFARE CENTER DAHLGREN DIV VA
|
| The Leading Edge magazine is produced by the Naval Surface Warfare Center, Dahlgren, Virginia. The purpose of the publication is to showcase technical excellence across the Warfare Centers and promote a broader awareness of the breadth and depth of knowledge and support available to the Navy and DoD. In this issue of The Leading Edge magazine, you will trace the rich history of directed-energy work at Dahlgren, gain insight into ... |
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| A Fundamental Key to Next-Generation Directed-Energy Systems |
Jan 2012 |
7 pages |
| Authors:
NAVAL SURFACE WARFARE CENTER DAHLGREN DIV VA
|
| Naval Surface Warfare Center, Dahlgren Division (NSWCDD), is meeting the demanding requirements of next-generation Directed-Energy (DE) systems with Class-E radiofrequency (RF) transmitter switch-mode amplifiers designed to operate at ultrahigh efficiency, greater than 90 percent. Having discovered the key to next-generation DE systems, researchers at NSWCDD are focusing on the urgent need to counter-improvised explosive device (IED) systems with small, lightweight, highly efficient transmitters that use switch-mode amplifiers. Considering the multiplicity ... |
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| All-optical Integrated Switches Based on Azo-benzene Liquid Crystals on Silicon |
Nov 2011 |
16 pages |
| Authors:
Antonio d'Alessandro; UNIVERSITA DI ROMA LA SAPIENZA ROMA (ITALY)
|
| Objective of this project is the design and fabrication of optically controlled switches using LC doped with azobenzene groups, with large nonlinear optical response, embedded in SiO2/Si grooves able to operate at telecom wavelengths (1500-1600 nm). Such LC mixtures are commercially available from Beam Engineering able also to synthesize custom mixtures for research purposes. In particular some fast switching mixtures are promising to obtain photonic devices with submicrosecond time responses. ... |
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| Horns as Particle Velocity Amplifiers |
Nov 2011 |
6 pages |
| Authors:
Dimitri M Donskoy; Benjamin A Cray; NAVAL UNDERSEA WARFARE CENTER DIV NEWPORT RI
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| Preliminary measurements and numerical predictions reveal that simple, and relatively small, horns generate remarkable amplification of acoustic particle velocity. For example, below 2 kHz, a 2.5 cm conical horn has a uniform velocity amplification ratio (throat-to-mouth) factor of approximately 3, or, in terms of a decibel level, 9.5 dB. It is shown that the velocity amplification factor depends on the horn's mouth-to-throat ratio as well as, though to a lesser ... |
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| High Power Multimode Fiber Master Oscillator Power Amplifier (MOPA) with Stimulated Brillouin Scattering (SBS) Beam Cleanup and Phase Conjugation |
Sep 2011 |
20 pages |
| Authors:
John E McElhenny; Jeffrey O White; Steven D Rogers; ARMY RESEARCH LAB ADELPHI MD SENSORS AND ELECTRON DEVICES DIRECTORATE
|
| This is a study, at the 102 W power level, of the feasibility of using stimulated Brillouin scattering (SBS) beam cleanup and wavefront reversal to obtain 105 W of single-mode output from a multi-mode fiber amplifier. These techniques allow power scaling by circumventing the problem of maintaining single-mode operation in a fiber with a large core. We have achieved 51-W peak power (34 W average) out of the beam cleanup ... |
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| Stimulated Brillouin Scattering Suppression in Fiber Amplifiers via Chirped Diode Lasers |
Sep 2011 |
18 pages |
| Authors:
Jeffrey O White; George Rakuljic; Carl E Mungan; ARMY RESEARCH LAB ADELPHI MD SENSORS AND ELECTRON DEVICES DIRECTORATE
|
| We propose to simultaneously suppress stimulated Brillouin scattering (SBS) and enable coherent combination by seeding fiber amplifiers with a linearly-chirped diode laser. The seed spectrum will appear broadband to suppress the SBS, but the well-defined chirp will have sufficient coherence to allow the active phasing of multiple amplifiers. The phasing can be accomplished without strict optical path-length matching by interfering each amplifier's output with a reference, processing the resulting signal ... |
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| Using a Volume Bragg Grating Instead of a Faraday Isolator in Lasers Incorporating Stimulated Brillouin Scattering Wavefront Reversal or Beam Cleanup |
29 Aug 2011 |
6 pages |
| Authors:
John E McElhenny; Jeffrey O White; Steven D Rogers; Tigran Sanamyan; Leonid B Glebov; Oleksiy Mokhun; Vadim I Smirnov; ARMY RESEARCH LAB ADELPHI MD
|
| A master-oscillator power-amplifier with stimulated Brillouin scattering (SBS) beam cleanup or wavefront reversal typically incorporates a Faraday isolator to outcouple the Stokes light, limiting the power scalability. Volume Bragg gratings (VBGs) have the potential for scaling to higher powers. We report here the results of tests on a VBG designed to resolve wavelengths 0.060 nm apart, corresponding to the 16 GHz frequency shift for SBS backscattering at 1064 nm in ... |
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| Single-cycle Pulse Synthesis by Coherent Superposition of Ultra-broadband Optical Parametric Amplifiers |
AUG 2011 |
45 pages |
| Authors:
Giulio Cerullo; POLITECNICO DI MILANO (ITALY)
|
| Ultrafast optical science has experienced major breakthroughs in the last years, driven by two main accomplishments: (i) generation of light pulses with duration of just a few cycles of the optical carrier wave; (ii) control of the carrier-envelope phase (CEP) of light pulses, enabling the production of optical waveforms with reproducible electric field. The generation of extremely short light pulses with controlled CEP allows exploring new frontiers of light-matter interaction, ... |
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| Compact & Ultra-High Resolution Terahertz Spectroscopic/Fingerprint System |
11 MAY 2011 |
32 pages |
| Authors:
Wei Shi; Eliot Petersen; Arturo Chavez-Pirson; NP PHOTONICS INC TUCSON AZ
|
| Report developed under topic #A10A-T013, contract W911NF-11-C-005. In Phase I, NP Photonics has successfully demonstrated the feasibility to implement the proposed fiber-based, compact, tunable, THz spectroscopic/fingerprinting system. We have achieved 0.212 mJ fiber laser pulses with transform-limited linewidth, bonded QPM-GaP crystals and the proposed THz crystal fiber converters for high power parametric THz source, THz waveguide modeling for high efficiency and high power THz generation, THz power 0.339 mW based ... |
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| Coherent Beam Combining of Fiber Amplifiers in a kW Regime |
21 APR 2011 |
8 pages |
| Authors:
Anthony D. Sanchez; Angel Flores; Thomas M. Shay; Chunte A. Lu; Craig Robin; Benjamin Pulford; Dane W. Hult; Ken B. Rowland; AIR FORCE RESEARCH LAB KIRTLAND AFB NM DIRECTED ENERGY DIRECTORATE
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| We report kW scale coherent beam combination (CBC) of both conventional silica fiber and photonic crystal fiber (PCF) amplifiers via LOCSET phase locking technology. Single-frequency CBC of 16 100W fiber lasers with 1.4 kW total output power is presented. In addition, kW scale CBC of novel SBS suppressive PCF amplifiers is presented. Three 350W PCF amplifiers arranged in a filled aperture configuration were combined into a single kW level laser ... |
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| Coherent Combining of High-Power Yb Fiber Amplifiers |
20 Apr 2011 |
9 pages |
| Authors:
Charles X Yu; Steven J Augst; Shawn M Redmond; Kris C Goldizen; Daniel V Murphy; Antonio Sanchez; Tso Y Fan; MASSACHUSETTS INST OF TECH LEXINGTON LINCOLN LAB
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| Commercial 0.5-kW Yb-doped fiber amplifiers have been characterized and been found to be suitable for coherent beam combining. Eight such fiber amplifiers have been coherently combined in a tiled-aperture configuration with 78% combining efficiency. The power-in-the-bucket vertical beam quality of the combined output is 1.25 times diffraction limited at full power. The beam-combining performance is independent of output power. |
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| System for Generating Coherent Single-Frequency Single Transverse Mode Light Pulses |
04 Mar 2011 |
17 pages |
| Authors:
Lee E Estes; NAVAL UNDERSEA WARFARE CENTER DIV NEWPORT RI
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| A system is provided to generate coherent single-frequency and single transverse mode light pulses. A laser produces a linearly-polarized continuous wave beam defined by a single longitudinal and transverse mode. A first rotator processes the beam such that optical polarization is rotated during a first time period and not rotated during a second and third time period. A second rotator is operated during the first period to rotate optical polarization ... |
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| Development of a 670 GHz Extended Interaction Klystron Power Amplifier |
Mar 2011 |
5 pages |
| Authors:
David Chernin; Richard Dobbs; Mark Hyttinen; Albert Roitman; Dave Berry; Monica Blank; Khanh Nguyen; Vadim Jabotinsky; Dean Pershing; Edward Wright; SCIENCE APPLICATIONS INTERNATIONAL CORP MCLEAN VA
|
| We describe our progress on the development of extended interaction klystron amplifiers operating at 670 GHz, meeting demanding requirements for output power gain, bandwidth, and efficiency. |
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| Highly Efficient Transmitter for High Peak to Average Power Ratio (PAPR) Waveforms |
19 JAN 2011 |
49 pages |
| Authors:
Alex Besprozvanny; Conni King; AETHERCOMM INC CARLSBAD CA
|
| Aethercomm has shown that a high efficiency power amplifier can be developed to enhance efficiency over specific bands over frequencies ranging between 400MHz through 4000MHz with up to 67% efficiencies. These frequencies can be extended down to 30MHz and offer consistent performances by adding additional band functionality allowing support for both HMS, GMR and various commercial applications. The high efficiency power amplifier performance levels shall be maintained with high PAR ... |
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| Low Temperature Noise Measurement of an InAs/GaSb-based nBn MWIR Detector |
Jan 2011 |
9 pages |
| Authors:
Vincent M Cowan; Christian P Morath; Stephen Myers; Nutan Gautam; Sanjay Krishna; AIR FORCE RESEARCH LAB KIRTLAND AFB NM SPACE VEHICLES DIRECTORATE
|
| Recent experiments on conventional p-on-n and n-on-p Type II superlattices (SLS) infrared detectors still indicate larger than theoretically predicted dark current densities, despite the well known suppression of the Auger recombination mechanism. Rather, dark current in SLS is thought to still be limited by trap-assisted tunneling in the depletion region and surface leakage currents resulting from lack of fully passivated mesa sidewalls. An emerging infrared detector technology utilizing a unipolar, ... |
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| Fast Light in Quantum Dot and Well Semiconductor Optical Amplifiers |
31 Oct 2010 |
10 pages |
| Authors:
Constance Chang-Hasnain; Pallab Bhattacharya; Shun-Lien Chuang; CALIFORNIA UNIV REGENTS BERKELEY
|
| Slow and fast light schemes are attractive for many applications including optical signal processing and RF phased array antennas. Semiconductor based schemes offer electrical control of velocity at very high bandwidths in an extremely compact device. Further they operate at room temperature and can be easily integrated into various optical systems. In this program, we used ultrafast nonlinearities in semiconductor optical amplifiers (SOAs) to achieve tunable time shifts at THz ... |
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| Digitally Driven Antenna for HF Transmission |
Sep 2010 |
10 pages |
| Authors:
Steven D Keller; W D Palmer; William T Joines; DUKE UNIV DURHAM NC
|
| An electrically small antenna connected directly to a complementary pair of switching transistors is driven with a pulsewidth modulated HF signal, eliminating the requirement for a frequency-dependent impedance-matching network. The intrinsic reactance of the transmit and receive antennas acts as a filter to recover the HF signal from the digital pulse train. This is defined here as the digitally driven antenna architecture. A circuit simulator with broadband equivalent-circuit models for ... |
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| F-16 Ventral Fin Buffet Alleviation Using Piezoelectric Actuators |
Sep-2009 |
122 pages |
| Authors:
Joseph S Browning; AIR FORCE INST OF TECH WRIGHT-PATTERSON AFB OH DEPT OF AERONAUTICS AND ASTRONAUTICS
|
| Buffet-induced vibrations can have a disastrous impact on aircraft structures. Early attempts at combating buffet vibrations included passive methods such as structural enhancements and leading edge fences. Active methods have shown greater promise, including active airflow control, control surface modulation, and active structural control using piezoelectric actuators. Surface mounted piezoelectric actuators impart directional strain reducing the negative effects associated with harmful vibration. The Block-15 F-16 ventral fin represents an aircraft ... |
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| Quantum Sensors Program |
Aug-2009 |
82 pages |
| Authors:
Z Dutton; S Guha; N Stelmakh; M Vasilyev; P Kumar; F Wong; J Shaprio; G Deibner; G Burdge; H Yuen; J Habif; HARRIS CORP MELBOURNE FL
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| The resolution of a homodyne LADAR can be enhanced significantly by applying quantum optical techniques in the receiver. With a quantum image enhancer (QIE) inserted between the receive optics and the detector of a LADAR, an angular cell resolution improvement of 10x can be realized. The QIE is comprised of two key elements-a squeezed vacuum injector (SVI) that restores the high spatial frequencies lost by attenuation in soft-aperture entrance optics ... |
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| Dense Heterogeneous Integration for InP Bi-CMOS Technology |
May 2009 |
7 pages |
| Authors:
Y Royter; P R Patterson; J C Li; K R Elliiott; T Hussain; M F Boag-O'Brien; J R Duvall; M C Montes; D A Hitko; J S Sewell; AIR FORCE RESEARCH LAB WRIGHT-PATTERSON AFB OH
|
| InP Bi-CMOS technology capable of wafer-scale device-level heterogeneous integration (HI) of InP HBTs and CMOS has been developed. With this technology, full simultaneous utilization of III-V device speed and CMOS circuit complexity is possible. Simple ICs and test structures have been fabricated, showing no significant CMOS or HBT degradation and high heterogeneous interconnect yield. The heterogeneously integrated differential amplifiers with record performance and HBTs with fT=400GHz were obtained. Thermal vias ... |
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| Wall-Plug Efficiencies of High-Power Free Electron Lasers Employing Energy Recovery Linacs |
23-Apr-2009 |
28 pages |
| Authors:
Phillip Sprangle; Joseph Penano; Bahman Hafizi; Ilan Ben-Zvi; NAVAL RESEARCH LAB WASHINGTON DC BEAM PHYSICS BRANCH
|
| In a high average power free electron laser (FEL) the wall-plug efficiency is of critical importance in determining the size, complexity and cost of the overall system. The wall-plug efficiency for the FEL oscillator and amplifier (uniform and tapered wiggler) are strongly dependent on the energy recovery process. A theoretical model for electron beam dynamics in the energy recovery linac is derived and applied to the acceleration and de-acceleration of ... |
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| High Average Power Diode Pumped Solid State Lasers: Power Scaling With High Spectral and Spatial Coherence |
30-Mar-2009 |
97 pages |
| Authors:
Robert L Byer; J Wisdom; K Urbanek; S Sinha; A Serpry; T Plettner; Y Lee; P S Kuo; R Gaume; H Bae; R Route; M Digonnet; S Wong; STANFORD UNIV CA
|
| The main program objective was the development of a kilowatt class, cw Nd:YAG diode-laser-pumped solid-state laser (DPSSL) with quantum noise limited amplitude and phase, 24by7 operation capability and the ability to be repaired while in operation. The approach was a master-oscillator power-amplifier (MOPA) laser utilizing a series of zig-zag slab power amplifiers stages. We developed fiber amplifiers at the 200W level to generate power with high optical efficiency that can ... |
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| UMD/NPS Free Electron Laser Research |
01-Dec-2008 |
77 pages |
| Authors:
Joseph Blau; William B Colson; MARYLAND UNIV COLLEGE PARK
|
| Simulations and theoretical analysis are used to study the development of high-average-power free electron lasers (FELs). Various existing and proposed FELs are studied, in both amplifier and oscillator configurations. Comparisons to experimental results show good agreement in each case. At the outset of this project, short Rayleigh length (SRL) optical cavities were proposed to reduce the optical intensity on the mirrors. Contrary to conventional wisdom, our simulations showed that an ... |
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| Continuous System-Level Scale for Comparing Laser Gain Media |
Dec-2008 |
24 pages |
| Authors:
Jeffrey O White; ARMY RESEARCH LAB ADELPHI MD SENSORS AND ELECTRON DEVICES DIRECTORATE
|
| Several quantities are proposed for facilitating a quantitative comparison of laser gain media, operating temperatures, pump, and laser wavelengths. They are based on the occupation probability of absorbing and emitting pump and laser levels. The system level, l, has a numerical value coinciding with conventional usage of the terms two-, three-, and four-level systems. The occupation factor has a value from -1 to +1, and is appropriate for describing an ... |
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| Plastic Digital Array Beamformer Development With Integrated High Efficiency Gallium-Nitride MMICs |
Dec-2008 |
9 pages |
| Authors:
J Gregory; C Fulton; A Wegener; B Perlman; W Chappell; PURDUE UNIV LAFAYETTE IN
|
| With the advent of highly efficient wide bandgap amplifiers, there is the possibility of generating high power outputs without using expensive packaging. The goal is to create a plastic panel of integrated radiators which have limited cooling while having an output with a minimum of 25 Watts per element with efficiencies above 60% at die level. Towards this end, the development of highly efficient GaN MMICs and plastic packaging is ... |
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| Single-Frequency, Yb-Free, Resonantly Cladding-Pumped Large Mode Area Er Fiber Amplifier for Power Scaling |
25-Jul-2008 |
4 pages |
| Authors:
Mark Dubinskii; Jun Zhang; Igor Kudryashov; ARMY RESEARCH LAB ADELPHI MD
|
| We report results for a single-frequency (SF) resonantly cladding-pumped Yb-free large mode area LMA erbium-doped fiber amplifier EDFA with nearly 50% slope efficiency based on a commercial 20/125 micrometer Er-doped double-clad LMA fiber with a core numerical aperture of 0.07. We believe that this is the original demonstration of a SF resonantly cladding-pumped LMA EDFA. We obtained a diffraction-limited SF output of 9.3 W, which is also a record power ... |
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| Miniature High Density Scandate Cathodes for Linear Beam Devices |
14-Jul-2008 |
31 pages |
| Authors:
Bernard K Vancil; Ivor Brodie; Arthur Carpenter; E BEAM INC BEAVERTON OR
|
| The work was an investigation of recent promising results by workers in China on scandate impregnated cathodes. The improvement in dispenser cathode performance due to additions of small quantities of scandium oxide has been known since at least the 1980s. But workers in China have produced breakthrough performance with verified current loadings to 100 A/cm2. These results have not been fully reproduced or understood by cathode researchers in this country. ... |
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| High-perveance W-band Sheet-beam Electron Gun Design |
Apr-2008 |
3 pages |
| Authors:
Khanh T Nguyen; John Pasour; Edward L Wright; John Petillo; Baruch Levush; NAVAL RESEARCH LAB WASHINGTON DC VACUUM ELECTRONICS BRANCH
|
| A design methodology for sheet-beam formation and solenoidal magnetic field transport is described, and a point design for a W-band amplifier gun and beam transport is presented. The gun topology flexibly permits adjustment of beam width to accommodate various interaction circuits while maintaining beam height. This topology has been employed in the design of a 19.5 kV, 3.6 A (1.32 micro-perv.) gun with beam final cross-section of approximately 4.2 mm ... |
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| Modeling of SBS Phase Conjugation in Multimode Step Index Fibers |
01-Mar-2008 |
106 pages |
| Authors:
Justin B Spring; AIR FORCE INST OF TECH WRIGHT-PATTERSON AFB OH GRADUATE SCHOOL OF ENGINEERING AND MANAGEMENT
|
| Stimulated Brillouin scattering in a multimode step-index fiber can be used to generate a counter-propagating, phase-conjugate beam that would prove useful in applications such as near diffraction limited, double-pass high-power amplifiers or coherent beam combination. Little modeling of such a fiber-based phase-conjugator has been done, making it difficult to make decisions about the right fiber to use. A numerical model was constructed with the aim of providing educated predictions about ... |
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| Theoretical Study of the Saturated Stage of a Relativistic Magnetron |
27-Feb-2008 |
6 pages |
| Authors:
D J Kaup; DJ KAUP INC WINTER SPRINGS FL
|
| The saturated stage of a magnetron or a cross-field amplifier is when the device has powered up and is steadily delivering power. Theoretical studies of this stage had suggested that when the dc current would become sufficiently large in comparison with the rf current, then no steady state solution could be expected to exist. Attempts were made to develop a numerical code which would allow one to numerically solve for ... |
|
| Four Dimensional Analysis of Free Electron Lasers in the Amplifier Configuration |
DEC 2007 |
81 pages |
| Authors:
Juan M. Aguilar; NAVAL POSTGRADUATE SCHOOL MONTEREY CA
|
| Free electron lasers (FELs) are devices used worldwide for several purposes. In the military, especially in the Navy, they can be used for self-defense against missiles, and small boats. Installed on a ship, an FEL represents a multi-mission, deep magazine, long range weapon. This thesis will describe briefly the basic components and principles of operation. It also explores, by simulations, the effects of changing some of the parameters that generate ... |
|
| Resource-Efficient Digital Communications: Research and Testbed Development in Support of Future Force Warrior and Joint Tactical Radio Systems |
NOV 2007 |
34 pages |
| Authors:
Thomas Fuja; Oliver Collins; Daniel Costello; Yih-Fang Huang; NOTRE DAME UNIV IN DEPT OF ELECTRICAL ENGINEERING
|
| This report describes the design and simulation of a bandwidth-efficient waveform suitable for the SLICE radio developed by ITT Aerospace/Communications; this waveform uses quadrature amplitude modulation (QAM) and low-complexity turbo codes developed at Notre Dame. The result is compared with another using continuous phase modulation (CPM). It is shown that the amplifier backoff required for QAM puts it at a disadvantage to CPM at spectral efficiencies where both are feasible ... |
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| Modulated Pulsed Laser Sources for Imaging Lidars |
OCT 2007 |
15 pages |
| Authors:
Scott Remington; Philip Battle; DEFENSE CONTRACT MANAGEMENT AGENCY TWIN CITIES FORT SNELLING MN
|
| This report summarizes work performed under Navy SBIR topic #N07-036 demonstrating the feasibility of using a pulsed 1O64nm laser diode to create pulses at 500 kHz with pulsewidths of 2O-25ns that are modulated at RF frequencies using an electro-optic modulator based on engineered nonlinear optical material. The modulated pulses are then amplified using a single-stage fiber amplifier and data is provided showing that powers of 10-13W will be ultimately output. ... |
|
| Laser Noise and its Impact on the Performance of Intensity-Modulation with Direct-Detection Analog Photonic Links |
10 AUG 2007 |
27 pages |
| Authors:
Vincent J. Urick; Preetpaul S. Devgan; Jason D. McKinney; James L. Dexter; NAVAL RESEARCH LAB WASHINGTON DC OPTICAL SCIENCES DIV
|
| The equations for radio-frequency gain, radio-frequency noise figure, compression dynamic range and spurious-free dynamic range are derived for an analog photonic link employing intensity modulation and direct detection. In particular, the impact of laser noise on the performance of an analog photonic link is demonstrated in terms of these metrics. We describe the experimental procedure for measuring laser noise and the measured laser noise spectra of lasers suitable for analog ... |
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| Design of a Compact, Optically Guided, Pinched, Megawatt Class Free-Electron Laser |
08 JUN 2007 |
31 pages |
| Authors:
Phillip Sprangle; Joseph Penano; Bahman Hafizi; NAVAL RESEARCH LAB WASHINGTON DC
|
| A conceptual design for a compact megawatt class FEL operating within atmospheric transmission windows is presented. The proposed FEL consists of an optically guided, pinched amplifier configuration driven by an RF linac. The gain length, efficiency, electron pulse slippage and the distance between the wiggler and first relay mirror are determined for a megawatt class design. Of particular concern in the design is the overall length of the optical system, ... |
|
| Wall-Plug Efficiencies of FEL Amplifiers and Oscillators Employing Energy Recovery Linacs |
06 JUN 2007 |
10 pages |
| Authors:
Phillip Sprangle; Joseph Penano; Bahman Hafizi; Ilan Ben-Zvi; NAVAL RESEARCH LAB WASHINGTON DC PLASMA PHYSICS DIV
|
| In a high average power FEL, the wall-plug efficiency is of critical importance in determining the size, complexity, and cost of the overall system. The wall-plug efficiency for the FEL oscillator and amplifier (uniform and tapered wiggler) are obtained and compared. In general, we find that the wall-plug efficiency for the tapered wiggler FEL amplifier is more than a factor of two greater than that of the oscillator. For typical ... |
|
| Terahertz Frequency Detection and Identification of Materials and Objects |
01-May-2007 |
9 pages |
| Authors:
X C Zhang; RENSSELAER POLYTECHNIC INST TROY NY
|
| There is early demonstration of amplification of THz wave in laser induced air plasma in the workshop, however, solid state THz amplifiers, the workhorse of conventional electronics, still do not exist at THz frequencies but the workshop felt that devices based on QCL and SLED structures will soon be a practical possibility. For broadband generation it is likely that femtosecond pulsed fibre laser THz sources will replace the Ti:sapphire system ... |
|
| Frequency Stabilization of a Waveguide Laser Using Pound-Drever-Hall |
SEP 2006 |
11 pages |
| Authors:
Michael Fanto; John Malowicki; Rebecca J. Bussjager; Paul Repak; Kelly Kramer; Daniel Casimir; Michael Hayduk; AIR FORCE RESEARCH LAB ROME NY SENSORS DIRECTORATE
|
| The generation of ultra-stable model-locked pulses in the 1550 regime is required for high resolution signal processing applications that include electro-optic sampling, transient probes, and optical clocks. More recently the frequency combs comprising these pulses have been applied to innovative methods of Arbitrary Waveform Generation (AWG) in the optical domain. Temporal stability in certain of these applications assumes the utmost importance. A proven approach to address the key issue, entails ... |
|
| Novel Fiber laser Source for Hyper-Sensitive, Long-Range LIDAR System |
18 JUN 2006 |
21 pages |
| Authors:
Kyunghwan Oh; KWANGJU INST OF SCIENCE AND TECHNOLOGY (REPUBLIC OF KOREA) DEPT OF MATERIALS SCIENCE AND ENGINEERING
|
| A study of an innovative waveguide structure including hollow optical fiber (HOF) with a central hole and rare earth doped ring core is investigated. The HOGF serves as a novel fiber laser and amplifier gain medium. The central air hole and glass ring core gives an access to chromatic dispersion control, while the rare earth doped ring and its adiabatic taper endows a new degree of freedom to design clad ... |
|
| Low Noise Infrasonic Sensor System with High Reduction of Natural Background Noise |
MAY 2006 |
49 pages |
| Authors:
F. Kern; S. Africk; P. Cataldi; R. Chaves; PHYSICAL SCIENCES INC ANDOVER MA
|
| Physical Sciences Inc. has developed a new type of infrasound piezocable sensor system under this program's SBIR Phase 1 and Phase 2 funding from DTRA. The sensors consist of continuous lengths of off-the-shelf radially poled polyvinylidene fluoride (PVDF) coaxial cables, theoretically of arbitrary length, specially terminated and connected to state of the art, ultra high input impedance quiet amplifiers, tailored to the unique characteristics of the sensor outputs. Test data ... |
|
| Electra: Repetitively Pulsed 700 J, 100 ns Electron Beam Pumped KrF Laser |
May-2006 |
5 pages |
| Authors:
J D Sethian; J L Giuliani; M F Wolford; F Hegeler; M C Myers; M Friedman; P Burns; R Jaynes; NAVAL RESEARCH LAB WASHINGTON DC PLASMA PHYSICS DIV
|
| This paper presents a brief overview of the Electra laser system and report on the most recent results. The laser system consists of an electron beam pumped main amplifier with an aperture of 30x30 cm2, an e-beam pumped 10x10 cm2 pre-amplifier, and a commercial discharge laser serving as the seed oscillator. The main amplifier, currently operated as an oscillator, has demonstrated single shot and rep-rate laser energies exceeding 700 J, ... |
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| Applications of Optical Coherent Transient Technology to Pulse Shaping, Spectral Filtering, Arbitrary Waveform Generation and RF Beamforming |
15 APR 2006 |
72 pages |
| Authors:
W. R. Babbitt; Mingzhen Tian; Kelvin Wagner; MONTANA STATE UNIV BOZEMAN DEPT OF PHYSICS
|
| Under research conducted by Montana State University and the University of Colorado, several optical coherent transient (OCT) devices was developed and demonstrated, including pulse shaping, arbitrary waveform generation, optical spectral filtering, time integrating correlator, Doppler shifted arrays, and optical beam scanning. OCT's are particularly well suited for RF photonic processing because of their large bandwidths (tens to hundreds of 6Hz), spectral resolution well below a MHz, and time-bandwidth products (TBP) ... |
|
| Semiconductor YBACUO Uncooled Focal Plane Arrays |
30 MAR 2006 |
16 pages |
| Authors:
Donald Butler; Zeynep Celik-Bulter; TEXAS UNIV AT ARLINGTON DEPT OF ELECTRICAL ENGINEERING
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| The research has developed a readout circuit design, microbolometer designs, fabricated the readout circuits utilizing the - MOSIS foundry service, tested the readout circuits, integrated microbolometers onto the readout circuit and tested microbolometers fabricated on the readout circuits. The readout circuit was designed according to the MOSIS AMI 1.6 micrometers low noise analog CMOS design rules. The readout circuits were designed using capacitive transimpedance amplifiers (CTIA) and constant current buffered ... |
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| Matrix Dilations via Cosine-Sine Decomposition |
FEB 2006 |
28 pages |
| Authors:
J. C. Allen; D. Arceo; SPACE AND NAVAL WARFARE SYSTEMS CENTER SAN DIEGO CA
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| This report originated in the Eta (infinity) Research Initiative of the Office of Naval research and the In-House Laboratory Independent Research (ILIR) Program of Space and Naval Warfare Systems Center San Diego (SSC San Diego). These programs focused on Eta (infinity) engineering for fleet applications wideband impedance matching and wideband amplifier optimization. Research in these applications produced several papers [33], [32], [2], [3], four patents, a book [1], and sparked ... |
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| Pump and Signal Taper for Airclad Fibers |
05 JAN 2006 |
8 pages |
| Authors:
Rene E. Kristiansen; Martin D. Nielsen; CRYSTAL FIBRE BIRKEROD (DENMARK)
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| This report results from a contract tasking Crystal Fibre A/S as follows: Crystal Fibre A/S will develop a taper/coupler solution to interface between a new polarization maintaining/polarizing amplifier fiber (DC-200-35-Yb-PM) and respectively pump fibers and a signal input fiber. The anticipated intermediate interface will be a 250 micron/0.46 NA pump guide and 20 micron MFD PM signal core fiber. We will seek to further interface this fiber to a tapered ... |
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| Multiple Channel Laser Beam Combination and Phasing Using Stimulated Brillouin Scattering in Optical Fibers |
22 DEC 2005 |
176 pages |
| Authors:
Brent W. Grime; AIR FORCE INST OF TECH WRIGHT-PATTERSON AFB OH SCHOOL OF ENGINEERING AND MANAGEMENT
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| Brightness scaling lasers using stimulated Brillouin scattering (SBS) in optical fibers is explored. A multiple-channel amplifier approach is used to increase the total power of a laser system while avoiding a significant burden on a single channel. The work explores two approaches utilizing both SBS beam cleanup and SBS piston error conjugation. A unique beam combiner that takes advantage of the SBS beam cleanup properties of a long, gradient-index multimode ... |
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| Electronically Reconfigurable Microwave Lens Antennas |
13 DEC 2005 |
54 pages |
| Authors:
Liang Xue; Vincent Fusco; QUEEN'S UNIV BELFAST (NORTHERN IRELAND)
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| The purpose of this report is to present the results of further investigations into the operation and design of two-dimensional Luneburg Lenses at 24 GHz, with the possibility for electronic control of their behavior. Various lens design techniques are illustrated; these include a holey dielectric lens (drilled dielectric), and a holey plate lens (etched holes on the upper metal plate). Ray tracing theory is presented which shows the general properties ... |
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