Photonics/Optics

Optical Tapers as White-Light WGM Resonators

Such resonators could be attractive for broad-band optical processing applications. NASA’s Jet Propulsion Laboratory, Pasadena, California A theoretical analysis has revealed that tapered optical waveguides could be useful as white-light whispering-gallery-mode (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.

Posted in: Tech Briefs, ptb catchall, Photonics, Briefs

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Moving Machine Vision to 64-Bits

A nearly geometric growth in the data requirements for many machine vision applications is pushing 32-bit processing to its limits. The challenge is not in processing power, however, but in addressing memory buffers as systems fill them with ever-increasing volumes of data. Moving vision systems to 64-bit operation can solve the data challenge, but will require fully-updated hardware and software support.

Posted in: Features, ptb catchall, Photonics, Articles

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Designing 3D Capabilities Into Handheld Displays

For 3D viewing to be convenient on small, portable devices, it must be autostereoscopic, thus eliminating the requirement for 3D “glasses.” The display devices must also provide 2D and 3D capability simultaneously, without sacrificing resolution or color vibrancy.

Posted in: ptb catchall, Applications, Photonics, Application Briefs

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Solar Rejection Filter for Large Telescopes

Filters help avoid thermal loading of the receiver by incident sunlight. NASA’s Jet Propulsion Laboratory, Pasadena, California To reject solar radiation photons at the front aperture for large telescopes, a mosaic of large transmission mode filters is placed in front of the telescope or at the aperture of the dome. Filtering options for effective rejection of sunlight include a smaller filter down-path near the focus of the telescope, and a large-diameter filter located in the front of the main aperture. Two types of large filters are viable: reflectance mode and transmittance mode.

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Free-Space Optical Interconnect Employing VCSEL Diodes

These optical interconnects are applicable for large-capacity interconnection between information-processing equipment. John H. Glenn Research Center, Cleveland, Ohio Sensor signal processing is widely used on aircraft and spacecraft. The scheme employs multiple input/output nodes for data acquisition and CPU (central processing unit) nodes for data processing. To connect 110 nodes and CPU nodes, scalable interconnections such as backplanes are desired because the number of nodes depends on requirements of each mission. An optical backplane consisting of vertical-cavity surface-emitting lasers (VCSELs), VCSEL drivers, photodetectors, and transimpedance amplifiers is the preferred approach since it can handle several hundred megabits per second data throughput. Conventional electrical interconnects severely limit the performance of high-speed networks because of parasitic resistance and capacitance, which limit bandwidth and cause clock signals to skew. Moreover, they cause pin congestion and require large and bulky multi-pin connectors.

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Critical Coupling Between Optical Fibers and WGM Resonators

Recipes address issues of phase matching, aperture matching, and suppressing intermodal coupling. NASA’s Jet Propulsion Laboratory, Pasadena, California Two recipes for ensuring critical coupling between a single-mode optical fiber and a whispering-gallery-mode (WGM) optical resonator have been devised. The recipes provide for phase matching and aperture matching, both of which are necessary for efficient coupling. There is also a provision for suppressing intermodal coupling, which is detrimental because it drains energy from desired modes into undesired ones.

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Designing Electro-Optical Sensors Using Collaborative Systems Engineering Technology

About 25% of space-borne electro-optical (EO) sensor programs in both the civil and National Security Space (NSS) communities have experienced reduced on-orbit reliability, as well as cost and schedule overruns of 100% or more1-3. Many of these EO sensor program over-runs can be largely attributed to delays, errors, and inadequate communication that occur at the many handoff points between team members and contractors in the current design process. This leads to the late discovery of technical problems, making them more expensive and time-consuming to fix.

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