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Ultra-Stable Beacon Source for Laboratory Testing of Optical Tracking

A prototype laser beacon assembly provides reference for testing tracking and pointing systems. The ultra-stable beacon source (USBS) provides a laser-beam output with a very low angular jitter and can be used as an absolute angular reference to simulate a beacon in the laboratory. The laser is mounted on the top of a very short (≈1 m) inverted pendulum (IP) with its optical axis parallel to the carbon fiber pendulum leg. The 85-cm, carbon fiber rods making up the leg are very lightweight and rigid, and are supported by a flex-joint at the bottom (see figure). The gimbal-mounted laser is a weight-adjustable load of about 1.5 kg with its center of rotation co-located with the center of percussion of the inverted pendulum. This reduces the coupling of transverse motion at the base of the pendulum to angular motion of the laser at the top.

Posted in: Photonics, Briefs, TSP

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Delaying Trains of Short Light Pulses in WGM Resonators

Delays would not be limited by resonator ring-down times. Suitably configured whispering-gallery-mode (WGM) optical resonators have been proposed as delay lines for trains of short light pulses. Until now, it has been common practice to implement an optical delay line as a coiled long optical fiber, which is bulky and tends to be noisy. An alternative has been to implement an optical delay line as a coupled-resonator optical waveguide (a chain of coupled optical resonators), which is compact but limits the width of the pulse spectrum to the width of an optical resonance and thereby places a lower limit on the duration of a pulse. In contrast, a delay line according to the proposal could be implemented as a single WGM resonator, and the pulses delayed by the resonator could be so short that their spectral widths could greatly exceed the spectral width of any single resonance.

Posted in: Photonics, Briefs

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Improving the Optical Quality Factor of the WGM Resonator

New iterative annealing and polishing increases the resonator’s finesse over the fundamental limit. Resonators usually are characterized with two partially dependent values: finesse (ℱ) and quality factor (Q). The finesse of an empty Fabry-Perot (FP) resonator is defined solely by the quality of its mirrors and is calculated asℱ = πR1/2/(1 – R).

Posted in: Photonics, Briefs

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Multiphysics Modeling Simplifies Analysis of Electrical and Electromagnetic Effects

Effects of lightning strikes and electromagnetic fields are simulated and modeled easily. The Saab Group has 17 business units, which are split into defense and security, systems and products, and aeronautics. Over the years, the company has taken advantage of the many paradigm shifts that have taken place in engineering analysis. One example is implementing comprehensive engineering methodologies that combine traditional experiments and testing with newer tools such as computer modeling and simulation. In the 1980s, Saab began applying largescale computer simulations, which were used to verify the lightning-protection components in the wings of the Gripen fighter aircraft.

Posted in: Briefs

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Geophysical Wave Propagation Calculation Using Multiphysics

Geologists can conduct in-field calculations without the need for large computing resources. The propagation of shear (S) and compression (P) waves within the Earth represents a critically important phenomenon for geologists. For many years, geologists have developed specialized computational programs to calculate wave propagation within complex geophysical regions. These programs have been instrumental in determining the location and characteristics of natural phenomena (e.g., earthquakes) and manmade activity (e.g., nuclear-blast tests).

Posted in: Briefs

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Simulating the Manufacturing Process of Ceramic Matrix Composites

Multiphysics simulation enables analysis of a range of physical phenomena occurring in the manufacturing process. Increasing the temperature at which jet aircraft engines operate would significantly improve thrust and fuel efficiency with reduced emissions. However, current engines operate within 50 degrees of the inherent melting point of the conventional materials used in engine construction. Thus, new materials capable of operating at higher temperatures for prolonged times must be developed and manufactured.

Posted in: Briefs

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3D Program Aids Design of Custom Iron Work

Software allows architectural iron works manufacturer to simplify the design process. Keuka Studios designs and manufactures custom architectural iron work and cable railings for commercial and home use. Keuka Studios first designs a product in CAD, CNC machines it to shape, and then takes the assembly to their forge, which adds the design elements. Dan White, founder and president of Keuka Studios, was frustrated by the limitations of existing design tools. Despite over 25 years of experience as a mechanical engineer with a deep working knowledge of 3D CAD, animation, rendering, and finite element analysis software, he could not be as creative with product design as he wanted.

Posted in: Software, Briefs

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