Photonics

Flexible Laser Design Targets Low-Volume Material Processing Needs

A flexible approach to diode-pumped laser design combines customized performance with cost-effective manufacturing. Coherent, Inc., Santa Clara, California Q-switched, diode-pumped solid-state lasers with an end-pumped cavity design are now widely used in micromachining, materials processing, marking, and related applications. They are used to process a broad range of materials including metals, glass, plastics, and semiconductors. But this application diversity creates a concomitant need for laser diversity. Namely, while each application requires superior reliability and performance, the definition of “superior performance” is very application-specific. For example, some metal ablation applications may benefit from a long laser pulse, whereas semiconductor scribing needs a short pulse and a very high pulse repetition rate.

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

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Aligning Optical Fibers by Means of Actuated MEMS Wedges

Wedges would be fabricated using gray-scale exposure of photoresist. Goddard Space Flight Center, Greenbelt, Maryland Microelectromechanical systems (MEMS) of a proposed type would be designed and fabricated to effect lateral and vertical alignment of optical fibers with respect to optical, electro-optical, optoelectronic, and/or photonic devices on integrated circuit chips and similar monolithic device structures. A MEMS device of this type would consist of a pair of oppositely sloped alignment wedges attached to linear actuators that would translate the wedges in the plane of a substrate, causing an optical fiber in contact with the sloping wedge surfaces to undergo various displacements parallel and perpendicular to the plane. In making it possible to accurately align optical fibers individually during the packaging stages of fabrication of the affected devices, this MEMS device would also make it possible to relax tolerances in other stages of fabrication, thereby potentially reducing costs and increasing yields.

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Optical Characterization of Molecular Contaminant Films

A theoretical model is correlated with measured spectral transmittances and VUV exposures of spacecraft optics. Lyndon B. Johnson Space Center, Houston, Texas A semi-empirical method of optical characterization of thin contaminant films on surfaces of optical components has been conceived. The method was originally intended for application to films that become photochemically deposited on such optical components as science windows, lenses, prisms, thin-film radiators, and glass solar-cell covers aboard spacecraft and satellites in orbit. The method should also be applicable, with suitable modifications, to thin optical films (whether deposited deliberately or formed as contaminants) on optical components used on Earth in the computer microchip laser communications and thin-film industries.

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10G and “Killer Apps” Excite Telecom Market in ‘07

In the optical communications industry, it’s important to look back before you look forward. History has a way of putting the future into perspective.

Posted in: Features, ptb catchall, Photonics, Articles

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Laser Diode Market Stays Hot in 2007

The high-power laser diode market has grown rapidly in the last twelve months, a trend that is set to continue throughout 2006 and beyond. The global market for laser systems is forecast to grow by 8% in 2006 to US $5.9 billion, with diode lasers alone growing by 8%.

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Optical Software in ‘07: Isn’t that Easy?

Optical software programs provide optical designers with the means to predict and analyze performance characteristics of optical systems without experimental prototyping. Looking ahead into 2007, optical software will continue to enhance optical design capabilities in several ways. Optical software developers are concentrating their efforts on improving communication channels between engineers in disparate fields who are asked to collaborate. In a word, the direction is “inter-operability.”

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Holographic Plossl Retroreflectors

Lightweight, inexpensive holographic optical elements would be used in place of lenses. Goddard Space Flight Center, Greenbelt, Maryland Holographic retroreflectors that function equivalently to Plossl eyepieces have been developed and used in free-space optical communication systems that utilize laser beams. Plossl eyepieces are well known among telescope designers. They have been adopted for use as retroreflectors and as focusing elements (for reception) and collimating elements (for transmission) in optical communication systems. A retroreflector that incorporates a Plossl eyepiece is termed a cat’s eye retroreflector (see figure).

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