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Wide-Band, High-Quantum-Efficiency Photodetector

This device could detect single photons. A design has been proposed for a photodetector that would exhibit a high quantum efficiency (as much as 90 percent) over a wide wavelength band, which would typically be centered at a wavelength of 1.55 μm. This and similar photodetectors would afford a capability for detecting single photons — a capability that is needed for research in quantum optics as well as for the practical development of secure optical communication systems for distribution of quantum cryptographic keys.

Posted in: Briefs, TSP, Physical Sciences

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Diffractive Combiner of Single-Mode Pump Laser-Diode Beams

Multiple beams can be combined without inducing multifrequency lasing. An optical beam combiner now under development would make it possible to use the outputs of multiple single-mode laser diodes to pump a neodymium: yttrium aluminum garnet (Nd:YAG) non-planar ring oscillator (NPRO) laser while ensuring that the laser operates at only a single desired frequency. Heretofore, an Nd:YAG NPRO like the present one has been pumped by a single multimode laser-diode beam delivered via an optical fiber. It would be desirable to use multiple pump laser diodes to increase reliability beyond that obtainable from a single pump laser diode. However, as explained below, simplistically coupling multiple multimode laser-diode beams through a fiber-optic combiner would entail a significant reduction in coupling efficiency, and lasing would occur at one or more other frequencies in addition to the single desired frequency.

Posted in: Briefs, TSP, Physical Sciences

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Distributed Control Standard Connects Industry Regardless of Bus

In the early days of modern automation, the use of microprocessor technology addressed the need for fast and efficient configuration of control logics through graphical methods that mimic the hardwired relay logics. Over the past 30 years, the automation community has put the emphasis on simplifying and standardizing the method of programming this new breed of controllers. From these efforts came the adoption of the IEC 61131-3 standard that specifies the programming languages for automation.

Posted in: Articles, Articles

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Bringing Modularity to MicroTCA

MicroTCA is a new specification that offers very high performance packed in a small form factor. The new specification is expected to be used in a wide variety of applications, including mil/aero, telecom edge, medical, enterprise and data, and scientific applications. However, there are so many possible configurations, it can be overwhelming. How can one develop various systems and offerings without starting from scratch — and the time to market, high costs, and implementation issues this brings? One solution is using modularity in MicroTCA designs. Prototyping and development of a new system enclosure design can be a time-consuming and costly process. Building upon a proven modular platform allows a wide range of design options with significantly reduced effort.

Posted in: Articles, Articles

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Filtered Conduction Empowers Mil-Spec Desert Systems

As embedded computing systems become more powerful, so are the challenges to protect and cool the payload. In the past few years, we have seen the power of a single board increase in most cases to over 100W per slot. To further challenge the designers, these systems are being deployed in rugged environments with a push to use COTS (commercial off-the-shelf) products. Recently, liquid-cooled systems have been developed to combat these However, there are some challenges with liquid cooling that can make this technology prohibitive. For example, not all boards are available in conduction- cooled format, or there may not be an external chiller/pump available to implement the liquid approach. So how does a designer handle an environment where there is no liquid coolant available, ambient temperatures hover around 55°C, the enclosure has a payload of 500W, and the client wants the system to operate on numerous rugged platforms (ground vehicle, rotary wing, UAV, etc.)? Oh, and the enclosure has to be sealed to protect the COTS boards from the harsh environments and EMI concerns. And with all of this, there is a desire to monitor the temperatures/ health of the system to protect the expensive payloads.

Posted in: Articles, Articles

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Data-Centric Network Integration Takes Headaches Out of Avionic Upgrades

Avionics systems are becoming more powerful and more dependent upon data exchanged between instruments. These instruments and subsystems reside on a network and must share time-critical data to achieve their mission. For example, targeting systems require real-time input of aircraft speed and attitude, as well as position and velocity data of the target. At the same time, additional bandwidth is required for data from onboard systems, such as GPS, airspeed and directional gyro, flight control systems, and dozens of other instruments and subsystems. As a result, network traffic is high, and potential data interactions can be highly complex. This complexity makes real-time integration of the data from disparate instruments during operational missions a significant challenge. Furthermore, upgrades of avionics and software applications during the useful life of the airframe means that new subsystems must be seamlessly integrated with legacy subsystems. In other words, data paths, interactions, and integration are not fixed forever. Today, aircraft systems typically are constructed to provide point-to-point communications between instruments and control systems that require realtime data. This approach has a significant impact on the complexity of the system and its subsequent maintainability. If an instrument is upgraded or replaced, the interfaces between it and other directly connected devices have the potential to change, requiring significant recoding and retesting.

Posted in: Application Briefs, Application Briefs

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Development Packages for M-Modules and PMCs

MEN Micro, Inc. (Ambler, PA) introduced the Universal Submodule (USM) development packages for M-Modules and PMCs that turn specialized I/O requirements into a series of standard products. The product implements a board’s desired functionality through one or more IP cores in an FPGA, augmenting the flexibility of M-Modules and PMCs with individual functionality. The same USM may be used on M-Modules, PMC modules, XMCs, and conduction- cooled PMC modules. Operating temperature is -40 to 85°C.

Posted in: Products, Products

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