Nano-technology poised for first (but not last) optical applications

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TECHNOLOGY

By ROBERT PEASE

Following more than 20 years of extensive research, nano-technology is about to make a significant impact in the telecommunications industry, with fiber-optic technology becoming its first "poster child." What was once considered science fiction in films like "Fantastic Voyage" is being commercialized as optical subcomponents, or subwavelength optical elements (SOEs).

First out of the gate with commercial nano-technology products in any industry sector appears to be Nano Opto Corp., a Somerset, NJ-based startup with proprietary nano-technology for designing and manufacturing components for optical networking. Founded in mid-2000 and based on 20 years of multimillion-dollar research in nano-photonics and nano-manufacturing, the company has already shipped prototype components to prospective customers for testing.

Nano-photonics sees the light
These SOEs take advantage of the physical principles that apply in the interaction of light and structures with dimensions far smaller than the wavelength of the light. With structural dimensions on the order of tens or a few hundreds of nanometers (hence "nano-technology"), the effects of reflection, refraction, and diffraction are highly localized and governed by a blend of classical optical and quantum effects.Th 88356

Polarizers, one subwavelength optical element being produced by NanoOpto Corp., are compared to the size of a dime. The dimensions for each polarizer are 1.4x1.4x0.5 mm. The smallest nano-structure size (on each device) measures about 100 nm.

"Because of the novel interaction between SOEs and light, large optical effects are realized on a very small scale," says Hubert Kostal, vice president of marketing and sales for NanoOpto. "In general, this allows a size reduction for the integrated component using the SOE and can also allow a reduction in the number of subcomponents required."

The advantages can be seen in the use of SOEs for polarization management. When light is incident on an SOE polarization beam splitter, for example, one polarization passes through and the other and is reflected back, creating a 180-degree separation in the space of less than a millimeter.

In a number of optical-component applications where each polarization must be processed independently, that can result in a much more compact integrated optical component. Also, because of the scale of the nano-structures used, SOEs can exhibit a broad acceptance angle to simplify integration and alignment, allowing both architectural flexibility and lower tolerances in the manufacturing process.

Proof in nano-technology
Nano-structures and their capabilities have undergone extensive research over two decades at several universities, including Princeton University, the University of Minnesota, and Harvard University. For telecom applications, the two key breakthroughs were in gaining a deeper understanding of the usable effects of interactions between light and nano-structures and devising methods to reliably and repeatedly manufacture those nano-structures. These breakthroughs opened the door for adoption in a major industry: optical communications.

"While most of the research work using nano-structures is being done in the biomedical field and consumer electronics areas, the first commercial production of what many believe is the next 'S' curve in the component and subcomponent fabrication area is going to be for subcomponents in the fiber-optic business," says Peter Bernstein, president of Infonautics Consulting Inc., a research-analyst firm in Ramsey, NJ. "Thus, the fiber-optic industry is going to be the proof for the entire field of nano-based technologies."

This revelation, says Bernstein, is creating both excitement and challenges for companies like NanoOpto. The communications industry will likely be highly scrutinized in how it harnesses and leverages the potential of such a disruptive technology. But there are benefits beyond size-cost and power consumption are always high on the list for the acceptance of any new telecom technology.

SOEs create the opportunity for integrated optical components to be built with much smaller dimensions. That equates to lower integration costs, smaller footprints, and less power consumption for equipment manufacturers. On a more immediate level, because of the simplicity of their integration, the use of SOEs can result in significant time savings and cost reductions in the manufacture of existing integrated optical components.

"Some typical products on the radar screen for telecommunications applications would include polarization management equipment, filters, and photodetectors," says NanoOpto's Kostal. "SOEs are a platform technology that can be rapidly and easily adapted to numerous customized applications."

Increasing popularity
As NanoOpto leverages its "first mover" advantage in commercializing SOEs and related technologies, the benefits of nano-photonics are sufficiently revolutionary to expect more companies to follow. In fact, Pirelli (Milan, Italy) recently announced a five-year alliance with the Massachusetts Institute of Technology to work on research and production of optical components for telecommunications based on nano-technologies. The company will invest $2 million in the initial year's research. The premise behind the agreement is that by reducing costs through miniaturizing components, the technology can evolve into a highly successful and profitable business.

The fiber-optic industry may be on the threshold of attainable miniaturization of optical-component products that pack so much functionality into very small spaces with great performance and lower costs that the vision of true end-to-end fiber in the access plant of the communications network will now be possible. "The rapid adoption of nano-based optical components could, in fact, be the final nail in the coffin for continued copper life-extension technology-this is that big a revolution in price performance," says Infonautics's Bernstein. "Gigabits to the home on all-optical networks at reasonable prices are finally no longer pipe dreams or light years away."

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