Matchbox-size tunable-laser architecture promises low cost, higher channel density

SRI International, a research Institute based in Silicon Valley, has developed an architecture that reportedly allows tunable laser technology to be deployed in fiberoptic networks at one-tenth of the physical size and cost of conventional technologies. With its Chameleon Telecom architecture, SRI believes it is bringing tunable laser technology to the price points necessary to allow service providers and network equipment manufacturers to penetrate the lucrative market of metropolitan area networks (MANs).

Available for licensing, the proprietary Chameleon Telecom design provides housing for ten tunable, self-calibrating lasers within a module that is about the size of a matchbook. The individual diode lasers in the package are based on the simplest known tunable laser technology, and, therefore, are easy to produce in any diode laser foundry. If the architecture is incorporated into DWDM networking gear used for maximizing fiberoptic capacity, SRI researchers report that equipment manufacturers could achieve a 90-percent cost reduction on a per-unit-bandwidth basis.

SRI's architecture for tunable laser modules addresses the problems that have prevented the technology's acceptance in the MAN market. Features include the following:

•Packaging. SRI's 10-channel module occupies a very small volume of 1.5 x 1.5 x 0.3 in., or just over two-thirds of a cubic inch, allowing network equipment manufacturers to maximize use of the available physical space.

•Stabilization. A microprocessor provides active control for the Chameleon Telecom module, providing very high spectral utilization (as low as one gigahertz channel spacing) and frequency stability (better than ±0.01 gigahertz). Real-time active frequency control allows the use of components that can be inexpensively manufactured within loose tolerances. This alleviates reliance on expensive, all-optical, conventional laser stabilization techniques.

•Self calibration. The module features a built-in, ultra-stable absolute frequency reference, making it self-calibrating and highly reliable.

Researchers from SRI add that the architecture minimizes manufacturing risks because it can be constructed with commercial off-the-shelf components. The design also enhances the capabilities of tunable diode laser technology by incorporating internal wavelength stabilization and referencing mechanisms, features that are typically only available at a premium.

For more information, visit SRI' web site.