Photonics

Compact 6-DOF Stage for Optical Adjustments

Adjustments can be made in all translational and rotational degrees of freedom. NASA’s Jet Propulsion Laboratory, Pasadena, California The figure depicts selected aspects of a six-degree-of-freedom (6-DOF) stage for mechanical adjustment of an optical component. The six degrees of freedom are translations along the Cartesian axes (x, y, and z) and rotations about these axes (θx, θy, and θz, respectively). Relative to prior such stages, this stage offers advantages of compactness, stability, and robustness, plus other advantages as described below.

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

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Fiber Optic Communications Systems

Communications and, more recently telecommunications, are needs deeply engrained in human history. These needs have significantly evolved over time enabling today’s content-rich (text, music, images and video, etc), real-time and multi-location exchanges through electrical, optical or, more broadly, electromagnetic signals conveyed by different media. Among the more versatile is optical fiber.

Posted in: Features, ptb catchall, Photonics, Articles

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Designing Converged Optical Ethernet Networks

Transport networks have witnessed two significant trends over the past half-decade or so. The first has been an explosion in the bandwidth these networks can support and the distances over which they can support it. This is due to the advent of cost-effective wavelength division multiplexing (WDM) and dense-WDM (DWDM), as well as a slew of technologies that extend transmission range, such as sophisticated optical amplifiers. The second has been the need to support a variety of traffic types (voice, video, data) and services: virtual private networks (VPNs), high-speed Internet (HSI), video-on-demand (VoD) and videoconferencing, and IPTV, to name a few. This is due to the need to simplify the network by collapsing intermediate layers and protocol stacks, thus reducing interface and node counts (and, hence, cost) in the carrier network. Thus, transport networks have migrated from being primarily voice-dominated to multi-service supporting infrastructures.

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

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Compact Two-Dimensional Spectrometer Optics

This unit would feature coarse and fine resolution along two orthogonal axes. NASA’s Jet Propulsion Laboratory, Pasadena, California The figure is a simplified depiction of a proposed spectrometer optical unit that would be suitable for incorporation into a remote-sensing instrumentation system. Relative to prior spectrometer optical assemblies, this unit would be compact and simple, largely by virtue of its predominantly two-dimensional character.

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Graphite/Cyanate Ester Face Sheets for Adaptive Optics

Unlike glass face sheets, these would be nearly unbreakable. Marshall Space Flight Center, Alabama It has been proposed that thin face sheets of wide-aperture deformable mirrors in adaptive-optics systems be made from a composite material consisting of cyanate ester filled with graphite. This composite material appears to offer an attractive alternative to low-thermal-expansion glasses that are used in some conventional optics and have been considered for adaptive-optics face sheets.

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Fractal-Based Encryption

Encryption methods based upon nonprobabilistic nondeterminism show promise in the optical age. In 1987 a discovery led to the formal proof that it is possible to use chaotic functions to arrive at a nonprobabilistic and nondeterministic method normal context of the operation of this system, and by using a virtual operational environment, the investigators are manipulating data in eight dimensions, which require a sixty-four discrete coordinate system, using eight nominative octets. Each octet is further addressed using the characters 0 through 9, and lower- or upper-case letters from A to Z. These provide the ability to address using normal ASCII characters. This format was chosen to ensure backward and forward compatibility with external third-party-written software.

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

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Fiber-Optic Liquid-Level Sensors

Liquid-level-measuring systems based on fiber-optics are under development as compact, lightweight alternatives to systems based on float gauges and other conventional sensors. For liquids that pose explosion hazards, fiber-optic sensors are inherently safer because they do not include electrical connections inside tanks. Fiber-optic sensors can be designed in many different forms to exploit reflection and transmission of light to measure liquid levels. Most of them are based on the effects of the indices of refraction of liquids on the waveguide properties of optical fibers: In a typical case, there is a loss of internal reflection of guided electromagnetic modes as a result of contact between the outer surface of optical fiber and a liquid. Hence, a substantial decrease in the light transmitted from one end of the fiber to the other is taken to indicate that liquid has come into contact with a suitably designed probe at the end of the fiber. A system capable of determining the level of liquid to within a known increment of depth could be constructed by placing the probes of a number of such sensors at known increments of depth in a tank.

Posted in: Tech Briefs, Photonics, Briefs

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