Browse Topic: Waveguides

Items (112)

Soft Prosthetic Hand Feels Surroundings via Stretchable Optical Waveguides

TBMG-3720007/01/2020

Fluid-powered soft actuators have shown potential in applications such as prosthetics and orthotics due to their natural motion. Robots using these actuators require stretchable sensors that can be embedded in their bodies for sophisticated functions; however, these sensors usually rely on the electrical properties of materials and composites to measure a signal and many suffer from hysteresis, complex fabrication, environmental instability, and material incompatibility with soft actuators.

Moving Precision Communication, Metrology, Quantum Applications from Lab to Chip

TBMG-3687805/01/2020

The field of photonic integration — the area of photonics in which waveguides and devices are fabricated as an integrated system onto a flat wafer — is relatively young compared to electronics. Photonic integration has focused on communications applications traditionally fabricated on silicon chips, because these are less expensive and more easily manufactured.

Optical Gyroscope-on-a-Chip

TBMG-3636504/01/2020

Gyroscopes are devices that help vehicles, drones, and wearable and handheld electronic devices know their orientation in three-dimensional space. Originally, gyroscopes were sets of nested wheels, each spinning on a different axis. But in a cellphone, a microelectro-mechanical sensor (MEMS) measures changes in the forces acting on two identical masses that are oscillating and moving in opposite directions. These MEMS gyroscopes are limited in their sensitivity, so optical gyroscopes have been developed to perform the same function but with no moving parts and a greater degree of accuracy using a phenomenon called the Sagnac effect.

Conformal Metasurface Coating Eliminates Crosstalk and Shrinks Waveguides

TBMG-3309110/01/2018

Researchers have developed a method to simultaneously control diverse optical properties of dielectric waveguides by using a two-layer coating, each layer with a near-zero thickness and weight.

Tech Briefs: September 2018

18AERP0909/01/2018

Enhanced SATCOMs for Unmanned Aerial Systems The Bus Too Tough to Die Combating Infrared Threats on the Battlefield Optical Interconnect Design Challenges in Space High-Performance Computing for the Next-Generation Combat Vehicle Merging Antenna and Electronics Boosts Energy and Spectrum Efficiency Integrated Magneto-Optical Devices for On-Chip Photonic Systems Development of magneto-optical (MO) materials could lead to a range of nonreciprocal optical devices for emerging standardized photonic integrated circuit (PIC) fabrication processes. Low Power Optical Phase Array Using Graphene on Silicon Photonics Electrostatic doping of 2D materials embedded in waveguides could enable ultrafast devices with unprecedented power. Spatial Resolution and Contrast of a Focused Diffractive Plenoptic Camera New technology captures spectral and spatial information of a scene in one snapshot while raising pixel counts and improving image quality. Ultracompact, High-Speed Field-Effect Optical

Researchers Create Precision Optical Components with Inkjet Printing

TBMG-3288109/01/2018

Researchers have developed an inkjet printing technique that can be used to print optical components such as waveguides. Because the printing approach can also fabricate electronics and microfluidics, it could advance a variety of devices such as optical sensors used for health monitoring and lab-on-a-chip devices that integrate and automate multiple laboratory functions onto a chip.

Ultracompact, High-Speed Field-Effect Optical Modulators

TBMG-3290709/01/2018

The major goals of this research project included two parts. First, an ultracompact plasmonic electro-optical (EO) modulator was to be developed and investigated for efficient intensity modulation. Second, an ultracompact and high-speed EO modulator based on a dielectric platform was to be developed for straightforward integration with existing CMOS technology. Both modulators were targeted to facilitate next-generation interconnects for integrated photonic circuits.

Ultracompact, High-Speed Field-Effect Optical Modulators

18AERP09_1009/01/2018

Conductive oxides-based modulator devices could provide promising candidates for ultra-compact and ultra-fast optical interconnects in future integrated photonic circuits. Army Research Office, Research Triangle Park, North Carolina The major goals of this research project included two parts. First, an ultracompact plasmonic electrooptical (EO) modulator was to be developed and investigated for efficient intensity modulation. Second, an ultracompact and high-speed EO modulator based on a dielectric platform was to be developed for straightforward integration with existing CMOS technology. Both modulators were targeted to facilitate next-generation interconnects for integrated photonic circuits. This work performed on this project explored novel conductive oxide-based slot waveguides based on the unique properties of indium-tin-oxide (ITO). This research was one of the first experimental attempts to demonstrate optical modulators at nanoscale, and one of the first systematic

Hirschman, Karl

Verification of Discrete and Packaged Photonic Device Technology Readiness

ARP6318 (Current)08/20/2018

This document is intended for discrete and integrated digital, wavelength division multiplexing (WDM), and analog/radio frequency (RF) photonic components developed for eventual transition to aerospace platforms. The document provides the reasons for verification of photonic device life test and packaging durability. The document focuses on pre-qualification activity at the optical component level to achieve TRL 6. The recommended tests in this document are intended to excite typical failure mechanisms encountered with photonic devices in an aerospace operating environment, and to build confidence that a technology is qualifiable during a program’s engineering and manufacturing development phase. This recommended practice is targeting components to support electrical-to-optical, optical-to-electrical, or optical-to-optical functionality. Passive optical waveguide, fiber optic cable, and connector components that are integral to a photonic package are included. Component and photonic

AS-3 Fiber Optics and Applied Photonics Committee

Integrating Optical Components into Existing Chip Designs

TBMG-2905606/01/2018

Moving from electrical communication to optical communication is attractive to chip manufacturers because it could significantly increase chips’ speed and reduce power consumption, an advantage that will grow in importance as chips’ transistor count continues to rise.

High Temperature Graphene-Peek Adhesive

TBMG-2795312/01/2017

Joining of composites can be a challenging issue. If adhesives are used, the joints are permanent and cannot be undone. If they need to be undone, inserts are often used and these inserts increase cost and weight. Additionally, fibers can be cut in the process leading to a part with weakened mechanical properties.

High Temperature Graphene-Peek Adhesive

17AERP12_0912/01/2017

Compounding graphene into polymers has the potential to improve various material properties, even at very low concentrations. Armament Research, Development and Engineering Center, Watervliet, New York Joining of composites can be a challenging issue. If adhesives are used, the joints are permanent and cannot be undone. If they need to be undone, inserts are often used and these inserts increase cost and weight. Additionally, fibers can be cut in the process leading to a part with weakened mechanical properties. Even with these drawbacks, most components that need to be joined are threaded together, allowing for removal of the parts at a later time. However, threaded connections are costly to design and manufacture, and are often the location of fatigue failures due to their inherent stress concentrations. From an environmental and cost standpoint, there is a large waste associated with the removal of material to form the threads, even more so in sectored threads, where up to half of

Lens-Coupled Dielectric Waveguides

TBMG-2516708/01/2016

NASA’s Jet Propulsion Laboratory has developed a low-loss dielectric waveguide that provides a simple, versatile, and flexible transmission medium. Dielectric waveguides — long, solid pieces of dielectric that confine electromagnetic waves — offer high bandwidth and low transmission loss compared to conventional metallic waveguides. Despite these advantages, practical use of these waveguides has been limited because a large fraction of signal power is lost at the state-of-the-art interconnects joining conventional metallic waveguides and dielectric waveguides. JPL’s interconnect solution uses lens coupling to reduce these losses by a factor of 10 or more, yielding a reliable, cost-effective alternative to conventional waveguides.

Advanced Laser Welding Technology Meets the Challenges of Medical Device Manufacturing

TBMG-2437604/01/2016

The medical industry continues to develop new devices that are smaller in size and more sophisticated in functionality. From in vitro diagnostics and treatment of chronic disease to completely taking over bodily functions, today’s medical devices are performing tasks that were hardly even imagined just a decade ago. In every case, their design requires perfection in form and function, and new assembly technologies are needed to meet these challenging requirements.

Quantitative Diagnostics of Multilayered Composite Structures with Ultrasonic Guided Waves

TBMG-2350312/01/2015

Aging infrastructure has a major impact on safety, increasing the need to assess damage severity. Machinery, systems, and components such as airplanes, cars, pumps, and pipes in the oil and chemical industry are subject to varying cyclic service loading and environmental influences. Sometimes multilayered coatings are used, requiring a high-resolution inspection to confirm the presence of a defect such as a delamination, and accurately locate and quantify its size. Highly attenuating materials may significantly increase the inspection time while limiting defect observability. Guided waves have been recognized as having excellent potential for nondestructive inspection. However, the presence of viscoelastic coatings used for corrosion protection is one of the major obstacles for guided wave inspection.

Automatic-Alignment Fiber Optic Coupling System for Optimal Signal Transmission

TBMG-2034508/01/2014

Using the current method of characterizing waveguides manufactured for research in optical communications, it can take up to 8 hours to characterize the waveguides on a single silicon wafer. Using the automatic computer automation system developed, the characterization process has been reduced to less than an hour. After the silicon wafer containing the waveguides is manufactured, the waveguides must be evaluated to determine the optical characteristics of the various waveguides on the silicon wafer.

Using Polyimide In 3D Thin Film Multilayer Circuitry

TBMG-1751910/01/2013

Today, the cost and complexity of all platforms and systems in military and defense technologies are being challenged by the need for high functionality in smaller but less expensive architecture, especially in light of current national budget challenges. In the area of RF and microwave electronics it is becoming evident that a move from two dimensional (2D) planar circuitry architecture to three dimensional (3D) thin film multilayer technology can result in dramatic reduction of chip size, increase of operation speed, and lower total module costs.

High-Power, High-Speed Electro-Optic Pockels Cell Modulator

TBMG-1720209/01/2013

Electro-optic modulators rely on a change in the index of refraction for the optical wave as a function of an applied voltage. The corresponding change in index acts to delay the wavefront in the waveguide. The goal of this work was to develop a high-speed, highpower waveguide-based modulator (phase and amplitude) and investigate its use as a pulse slicer. The key innovation in this effort is the use of potassium titanyl phosphate (KTP) waveguides, making the high-power, polarization- based waveguide amplitude modulator possible. Furthermore, because it is fabricated in KTP, the waveguide component will withstand high optical power and have a significantly higher RF modulation figure of merit (FOM) relative to lithium niobate. KTP waveguides support highpower TE and TM modes — a necessary requirement for polarization-based modulation as with a Pockels cell.

On-Chip Power-Combining for High-Power Schottky Diode- Based Frequency Multipliers

TBMG-1546701/01/2013

A 1.6-THz power-combined Schottky frequency tripler was designed to handle approximately 30 mW input power. The design of Schottky-based triplers at this frequency range is mainly constrained by the shrinkage of the waveguide dimensions with frequency and the minimum diode mesa sizes, which limits the maximum number of diodes that can be placed on the chip to no more than two. Hence, multiple-chip power-combined schemes become necessary to increase the power-handling capabilities of high-frequency multipliers. However, the traditional powercombining topologies that are used below 1 THz present some inconvenience beyond 1 THz. The use of Y-junctions or hybrid couplers to divide/combine the input/output power at these frequency bands increases unnecessarily the electrical path of the signal in the range of frequencies where waveguide losses are considerable. Also, guaranteeing a perfect alignment of the very small chips during assembly, in order to preserve the balanced nature of the

Adjusting Permittivity by Blending Varying Ratios of SWNTs

TBMG-1508511/01/2012

A new composite material of singlewalled carbon nanotubes (SWNTs) displays radio frequency (0 to 1 GHz) permittivity properties that can be adjusted based upon the nanotube composition. When varying ratios of raw to functionalized SWNTs are blended into the silicone elastomer matrix at a total loading of 0.5 percent by weight, a target real permittivity value can be obtained between 70 and 3. This has particular use for designing materials for microwave lenses, microstrips, filters, resonators, high-strength/low-weight electromagnetic interference (EMI) shielding, antennas, waveguides, and low-loss magneto-dielectric products for applications like radome construction.

Theory of a Traveling Wave Feed for a Planar Slot Array Antenna

TBMG-1486910/01/2012

Planar arrays of waveguide-fed slots have been employed in many radar and remote sensing applications. Such arrays are designed in the standing wave configuration because of high efficiency. Traveling wave arrays can produce greater bandwidth at the expense of efficiency due to power loss in the load or loads. Traveling wave planar slot arrays may be designed with a long feed waveguide consisting of centered-inclined coupling slots. The feed waveguide is terminated in a matched load, and the element spacing in the feed waveguide is chosen to produce a beam squinted from the broadside.

Mid- and Long-IR Broadband Quantum Well Photodetector

TBMG-1358005/01/2012

A single-stack broadband quantum well infrared photodetector (QWIP) has been developed that consists of stacked layers of GaAs/AlGaAs quantum wells with absorption peaks centered at various wavelengths spanning across the 9-to-11-μm spectral regions. The correct design of broadband QWIPs was a critical step in this task because the earlier implementation of broadband QWIPs suffered from a tuning of spectral response curve with an applied bias. Here, a new QWIP design has been developed to overcome the spectral tuning with voltage that results from nonuniformity and bias variation of the electrical field across the detector stacks with different absorption wavelengths.

Integrated Optics Achromatic Nuller for Stellar Interferometry

TBMG-1268601/01/2012

This innovation will replace a beam combiner, a phase shifter, and a mode conditioner, thus simplifying the system design and alignment, and saving weight and space in future missions. This nuller is a dielectric-waveguidebased, four-port asymmetric coupler. Its nulling performance is based on the mode-sorting property of adiabatic asymmetric couplers that are intrinsically achromatic. This nuller has been designed, and its performance modeled, in the 6.5-micrometer to 9.25-micrometer spectral interval (36% bandwidth). The calculated suppression of starlight for this 15-cm-long device is 10–5 or better through the whole bandwidth. This is enough to satisfy requirements of a flagship exoplanet-characterization mission.

Excitation of a Parallel Plate Waveguide by an Array of Rectangular Waveguides

TBMG-1082909/01/2011

This work addresses the problem of excitation of a parallel plate waveguide by an array of rectangular waveguides that arises in applications such as the continuous transverse stub (CTS) antenna and dual-polarized parabolic cylindrical reflector antennas excited by a scanning line source. In order to design the junction region between the parallel plate waveguide and the linear array of rectangular waveguides, waveguide sizes have to be chosen so that the input match is adequate for the range of scan angles for both polarizations.

Analysis of Microwave Radiation

TBMG-1090909/01/2011

Microwave heating is an important process for many commercial, industrial, and household applications. Industrial microwave ovens are widely used for chemical processing, agri-food, medical products, and consumer products applications. Resonant cavities are often used to speed up chemical reactions, and have the advantages of being small and producing efficient distributions of microwave energy. These multimode cavities can be considered as batch ovens where products can be treated; alternatively, microwave tunnels with multiple waveguides can be used to provide continuous production.

Ridge Waveguide Structures in Magnesium-Doped Lithium Niobate

TBMG-1014106/01/2011

This work proposes to establish the feasibility of fabricating isolated ridge waveguides in 5% MgO:LN. Ridge waveguides in MgO:LN will significantly improve power handling and conversion efficiency, increase photonic component integration, and be well suited to space-based applications. The key innovation in this effort is to combine recently available large, high-photorefractive-damage-threshold, z-cut 5% MgO:LN with novel ridge fabrication techniques to achieve high-optical power, low-cost, high-volume manufacturing of frequency conversion structures. The proposed ridge waveguide structure should maintain the characteristics of the periodically poled bulk substrate, allowing for the efficient frequency conversion typical of waveguides and the high optical damage threshold and long lifetimes typical of the 5% doped bulk substrate. The low cost and large area of 5% MgO:LN wafers, and the improved performance of the proposed ridge waveguide structure, will enhance existing measurement

Ridge Waveguide Structures in Magnesium-Doped Lithium Niobate

TBMG-TB-01014106/01/2011

Dielectric Covered Planar Antennas at Submillimeter Wavelengths for Terahertz Imaging

TBMG-988805/01/2011

Most optical systems require antennas with directive patterns. This means that the physical area of the antenna will be large in terms of the wavelength. When non-cooled systems are used, the losses of microstrip or coplanar waveguide lines impede the use of standard patch or slot antennas for a large number of elements in a phased array format.

Higher Order Mode Coupling in Feed Waveguide of a Planar Slot Array Antenna

TBMG-961104/01/2011

A simple technique was developed to account for the higher order mode coupling between adjacent coupling slots in the feed waveguide of a planar slot array. The method uses an equation relating the slot impedance to the slot voltage and a reaction integral involving the equivalent magnetic current of the slot aperture and the magnetic field coupled from an adjacent slot.

In Situ Guided Wave Structural Health Monitoring System

TBMG-901701/01/2011

Aircraft engine rotating equipment operates at high temperatures and stresses. Noninvasive inspection of microcracks in those components poses a challenge for nondestructive evaluation. A low-cost, low-profile, high-temperature ultrasonic guided wave sensor was developed that detects cracks in situ. The transducer design provides nondestructive evaluation of structures and materials.

Multiple Differential-Amplifier MMICs Embedded in Waveguides

TBMG-888812/01/2010

Compact amplifier assemblies of a type now being developed for operation at frequencies of hundreds of gigahertz comprise multiple amplifier units in parallel arrangements to increase power and/or cascade arrangements to increase gains. Each amplifier unit is a monolithic microwave integrated circuit (MMIC) implementation of a pair of amplifiers in differential (in contradistinction to single-ended) configuration.

Update on Waveguide-Embedded Differential MMIC Amplifiers

TBMG-889012/01/2010

There is an update on the subject matter of “Differential InP HEMT MMIC Amplifiers Embedded in Waveguides” (NPO-42857) NASA Tech Briefs, Vol. 33, No. 9 (September 2009), page 35. To recapitulate: Monolithic microwave integrated-circuit (MMIC) amplifiers of a type now being developed for operation at frequencies of hundreds of gigahertz contain InP high-electron-mobility transistors (HEMTs) in a differential configuration. The MMICs are designed integrally with, and embedded in, waveguide packages. The instant work does not mention InP HEMTs but otherwise reiterates part of the subject matter of the cited prior article, with emphasis on the following salient points:

Demonstration of a Submillimeter-Wave HEMT Oscillator Module at 330 GHz

TBMG-805706/01/2010

In this work, radial transitions have been successfully mated with a HEMT-based MMIC (high-electron-mobility-transistor-based monolithic microwave integrated circuit) oscillator circuit. The chip has been assembled into a WR2.2 waveguide module for the basic implementation with radial E-plane probe transitions to convert the waveguide mode to the MMIC coplanar waveguide mode. The E-plane transitions have been directly integrated onto the InP substrate to couple the submillimeter-wave energy directly to the waveguides, thus avoiding wirebonds in the RF path. The oscillator demonstrates a measured 1.7 percent DC-RF efficiency at the module level.

MMIC Amplifiers and Wafer Probes for 350 to 500 GHz

TBMG-805906/01/2010

Several different experimental monolithic microwave integrated circuit (MMIC) amplifiers have been designed to operate in frequency bands ranging from 350 to 500 GHz and were undergoing fabrication at the time of reporting the information for this article. Probes for on-wafer measurement of electrical parameters [principally, the standard scattering parameters (“S” parameters)] of these amplifiers have been built and tested as essential components of systems to be used in quantifying the performances of the amplifiers. These accomplishments are intermediate products of a continuing effort to develop solid-state electronic amplifiers capable of producing gain at ever-higher frequencies, now envisioned to range up to 800 GHz. Such amplifiers are needed for further development of compact, portable imaging systems and scientific instruments for a variety of potential applications that include detection of hidden weapons, measuring winds, and measuring atmospheric concentrations of certain

Novel Microstrip-to-Waveguide Feed Employing a Double-Y Junction

TBMG-793605/01/2010

Previous microstrip-to-waveguide transitions either required a hermetically sealed waveguide configuration, or a balun that needed to be tuned according to the frequency band of interest. In this design, the balun is realized using a double-Y junction to transition from microstrip to coplanar strip feeding a quasi-Yagi dipole array (see figure). The length of the feed (Lf) extending into the waveguide is 15.54 mm. The length of the ground plane below the ULTRALAM substrate is 7.75 mm. The lengths L1, L2, and L3 are 8.50 mm, 4.38 mm, and 2.14 mm, respectively. These lengths were computed via a preliminary optimization aimed at improving the return loss at the band edges.

Improved Model of Spectral Response of an HEB Mixer

TBMG-TB-00747702/12/2010

Fringing fields and the inductance of the HEB microbridge are taken into account. An improved mathematical model enables the somewhat more accurate prediction of the spectral response of a mixer circuit (see figure) that comprises a twin-slot antenna coupled via coplanar waveguides to a hot-electron bolometer (HEB). The development of the improved model is part of a continuing effort to understand and overcome the limitations of circuit models in order to enhance capabilities for designing and analyzing heterodyne mixers to operate at frequencies in the terahertz range.

Quad-Chip Double-Balanced Frequency Tripler

TBMG-716302/01/2010

Solid-state frequency multipliers are used to produce tunable broadband sources at millimeter and submillimeter wavelengths. The maximum power produced by a single chip is limited by the electrical breakdown of the semiconductor and by the thermal management properties of the chip. The solution is to split the drive power to a frequency tripler using waveguides to divide the power among four chips, then recombine the output power from the four chips back into a single waveguide.

Optical Tapers as White-Light WGM Resonators

TBMG-TB-00663112/23/2009

Such resonators could be attractive for broad-band optical processing applications. A theoretical analysis has revealed that tapered optical waveguides could be useful as white-light whispering-gallerymode (WGM) optical resonators. The compactness and the fixed-narrow-frequency- band nature of the resonances of prior microdisk and microsphere WGM resonators are advantageous in low-power, fixed-narrow-frequency-band applications. However for optical-processing applications in which there are requirements for power levels higher and/or spectral responses broader than those of prior microdisk and microsphere WGM resonators, white-light WGM resonators in the form of optical tapers would be preferable.

Inventions Utilizing Microfluidics and Colloidal Particles

TBMG-637012/01/2009

Several related inventions pertain to families of devices that utilize microfluidics and/or colloidal particles to obtain useful physical effects. The families of devices can be summarized as follows:

Differential InP HEMT MMIC Amplifiers Embedded in Waveguides

TBMG-562309/01/2009

Monolithic microwave integrated-circuit (MMIC) amplifiers of a type now being developed for operation at frequencies of hundreds of gigahertz contain InP high- electron-mobility transistors (HEMTs) in a differential configuration. The differential configuration makes it possible to obtain gains greater than those of amplifiers having the single-ended configuration. To reduce losses associated with packaging, the MMIC chips are designed integrally with, and embedded in, waveguide packages, with the additional benefit that the packages are compact enough to fit into phased transmitting and/or receiving antenna arrays.

Dual-Polarization, Sideband-Separating, Balanced Receiver for 1.5 THz

TBMG-550508/01/2009

A proposed heterodyne receiver would be capable of detecting electromagnetic radiation in both of two orthogonal linear polarizations, separating sidebands, and providing balanced outputs in a frequency band centered at 1.5 THz with a fractional bandwidth >40 percent. Dual-polarization, sideband-separating, and balanced-output receivers are well- known and have been used extensively at frequencies up to about 100 GHz; and there was an earlier proposal for such a receiver for frequencies up to 900 GHz. However, the present proposal represents the first realistic design concept for such a receiver capable of operating above 1 THz. The proposed receiver is intended to be a prototype of mass-producible receiver units, operating at frequencies up to 6 THz, that would be incorporated into highly sensitive heterodyne array instruments to be used in astronomical spectroscopic and imaging studies.

Integrated Miniature Arrays of Optical Biomolecule Detectors

TBMG-1097507/01/2009

Integrated miniature planar arrays of optical sensors for detecting specific bio-chemicals in extremely small quantities have been proposed. An array of this type would have an area of about 1 cm2. Each element of the array would include an optical microresonator that would have a high value of the resonance quality factor (Q ≈ 107). The surface of each microresonator would be derivatized to make it bind molecules of a species of interest, and such binding would introduce a measurable change in the optical properties of the microresonator. Because each microresonator could be derivatized for detection of a specific biochemical different from those of the other microresonators, it would be possible to detect multiple specific biochemicals by simultaneous or sequential interrogation of all the elements in the array. Moreover, the derivatization would make it unnecessary to prepare samples by chemical tagging.

Integrated Miniature Arrays of Optical Biomolecule Detectors

TBMG-545307/01/2009

Integrated miniature planar arrays of optical sensors for detecting specific biochemicals in extremely small quantities have been proposed. An array of this type would have an area of about 1 cm2. Each element of the array would include an optical microresonator that would have a high value of the resonance quality factor (Q ≈ 107). The surface of each microresonator would be derivatized to make it bind molecules of a species of interest, and such binding would introduce a measurable change in the optical properties of the microresonator. Because each microresonator could be derivatized for detection of a specific biochemical different from those of the other microresonators, it would be possible to detect multiple specific biochemicals by simultaneous or sequential interrogation of all the elements in the array. Moreover, the derivatization would make it unnecessary to prepare samples by chemical tagging.

T/R Multi-Chip MMIC Modules for 150 GHz

TBMG-527506/01/2009

Modules containing multiple monolithic microwave integrated-circuit (MMIC) chips have been built as prototypes of transmitting/receiving (T/R) modules for millimeter-wavelength radar systems, including phased-array radar systems to be used for diverse purposes that could include guidance and avoidance of hazards for landing spacecraft, imaging systems for detecting hidden weapons, and hazard-avoidance systems for automobiles. Whereas prior landing radar systems have operated at frequencies around 35 GHz, the integrated circuits in this module operate in a frequency band centered at about 150 GHz. The higher frequency (and, hence, shorter wavelength), is expected to make it possible to obtain finer spatial resolution while also using smaller antennas and thereby reducing the sizes and masses of the affected systems.

Modal Filters for Infrared Interferometry

TBMG-1095005/01/2009

NASA's Jet Propulsion Laboratory, Pasadena, California

Manipulating Neutral Atoms in Chip-Based Magnetic Traps

TBMG-519105/01/2009

Several techniques for manipulating neutral atoms (more precisely, ultracold clouds of neutral atoms) in chip-based magnetic traps and atomic waveguides have been demonstrated. Such traps and waveguides are promising components of future quantum sensors that would offer sensitivities much greater than those of conventional sensors. Potential applications include gyroscopy and basic research in physical phenomena that involve gravitational and/or electromagnetic fields. The developed techniques make it possible to control atoms with greater versatility and dexterity than were previously possible and, hence, can be expected to contribute to the value of chip-based magnetic traps and atomic waveguides.

Modal Filters for Infrared Interferometry

TBMG-522605/01/2009

Modal filters in the ≈10-μm spectral range have been implemented as planar dielectric waveguides in infrared interferometric applications such as searching for Earth-like planets. When looking for a small, dim object (“Earth”) in close proximity to a large, bright object (“Sun”), the interferometric technique uses beams from two telescopes combined with a 180° phase shift in order to cancel the light from a brighter object. The interferometer baseline can be adjusted so that, at the same time, the light from the dimmer object arrives at the combiner in phase. This light can be detected and its infrared (IR) optical spectra can be studied. The cancellation of light from the “Sun” to ≈106 is required; this is not possible without special devices — modal filters — that equalize the wavefronts arriving from the two telescopes.

Traveling-Wave Maser for 32 GHz

TBMG-515905/01/2009

The figure depicts a traveling-wave ruby maser that has been designed (though not yet implemented in hardware) to serve as a low-noise amplifier for reception of weak radio signals in the frequency band of 31.8 to 32.3 GHz. The design offers significant improvements over previous designs of 32-GHz traveling-wave masers. In addition, relative to prior designs of 32-GHz amplifiers based on high-electron-mobility transistors, this design affords higher immunity to radio-frequency interference and lower equivalent input noise temperature.

Manipulating Neutral Atoms in Chip-Based Magnetic Traps

TBMG-TB-00519104/30/2009

Magnetic-field gradients are used to accelerate and decelerate atoms. Several techniques for manipulating neutral atoms (more precisely, ultracold clouds of neutral atoms) in chip-based magnetic traps and atomic waveguides have been demonstrated. Such traps and waveguides are promising components of future quantum sensors that would offer sensitivities much greater than those of conventional sensors. Potential applications include gyroscopy and basic research in physical phenomena that involve gravitational and/or electromagnetic fields. The developed techniques make it possible to control atoms with greater versatility and dexterity than were previously possible and, hence, can be expected to contribute to the value of chip-based magnetic traps and atomic waveguides.

In-Phase Power-Combined Frequency Tripler at 300 GHz

TBMG-352702/01/2009

This design starts with commercial 85- to 115-GHz sources that are amplified to as much as 250 mW using power amplifiers developed for the Herschel Space Observatory. The frequency is then tripled using a novel waveguide GaAs Schottky diode frequency tripler. This planar diode produces 26 mW at 318 GHz. Peak conversion efficiency is over 15 percent, and the measured bandwidth of about 265–330 GHz is limited more by the driving source than by the tripler itself.

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