In late 1998, Accuwave Corporation ceased operations and went into bankruptcy. The firm specialized in the development of holographic communications systems able to increase substantially the number of signals that can be transmitted in a single strand of fiber-optic cable. Fully implemented, the technology could have significantly reduced the cost per transmission. The technology was based on the concept of wavelength division multiplexing (WDM), which transmits light of more than one wavelength through a single optical fiber, separating the individual wavelengths at the receiver. Such systems must discriminate among the different wavelengths and so are limited by the accuracy of the multiplexing and demultiplexing optics. Accuwave had previously developed a unique approach to WDM using volume holography: holograms "written" in the interior of thick crystals of photorefractive (light-bending) materials. In the demultiplexer crystal, for example, multiwavelength light enters one end of the crystal and encounters a series of holographic gratings - each tuned to deflect a specific wavelength of light - that separate the light signals of different wavelengths. Accuwave had demonstrated the individual elements of a system that could multiplex wavelengths more than 10 times better than the current state of the art at visible wavelengths. With its ATP funding, Accuwave extended its technology to the infrared wavelengths used for long-distance telecommunications, and designed a prototype WDM system. The company was able to form important alliances with research partners. However, another company beat them to market with a competing system operating in the same infrared wavelengths. Accuwave continued to work toward completion of its WDM multiplexer, which it believes provides multiplexing capabilities of higher signal accuracy, with more channels per fiber and in a smaller package than the products offered by competitors. Plans were developed for sale of a WDM system in the bulk-signal-transmission market. Several component products were launched, including wavelength controllers, wavelength lockers and fiber-optic collimators, all sold internationally to producers of WDM systems. With its potential to increase the number of signals that a single optical fiber could carry, the Accuwave technology could have significantly affected the cost of communications via fiber-optic cables, particularly if used for undersea applications. The technology had the potential to double and redouble the number of signals per fiber many times over, with the count possibly reaching as many as 80 signals per fiber. In addition to applications in the bulk-signal-transmission market, the technology could provide greater cable bandwidth to homes and offices for use with high-definition TV and to the closed-circuit TV market, particularly for security uses. However, the firm focused resources to the telecommunications applications.
