Sol-gel process cuts device costs

17 Jun 2002

A single-step sol-gel process promises to cut manufacturing costs for telecoms components.

Terahertz Photonics of the UK has developed a single-step sol-gel process that it says will dramatically cut the cost of making optical components such as arrayed waveguide gratings, variable optical attenuators and couplers.

It claims its Solica process is ten times cheaper than alternative methods. The process also provides a platform for a range of new devices that are both more compact and have more features than standard components.

Navin Suyal, director of planar lightwave circuit materials at Terahertz Photonics said: "We believe that our Solica process is capable of changing the present cost performance-curve of this sector, which will enable the next generation of metro, access and fiber-to-the home applications."

He says that Terahertz developed the process in order to overcome the limitations of existing expensive gas techniques.

The Solica process involves the synthesis of a patented sol mixture followed by a single spinning, drying and firing operation. This means that optical-quality glass layers up to 10 µm can be made using a single liquid-based process.

The process employs standard tools and techniques from the semiconductor industry for both the deposition of the silica and the subsequent lithography.

As the silica produced by this process is heated to around 1150°C, it contains no organic additives which are present in the initial sol. The silica produced using the Solica process does not have any impurities which could limit its performance.

The silica layers may be doped to give a refractive index in the range of 1.45 to 1.50. This enables the creation of so called super-high delta waveguides in which the difference in the index between core and cladding can be as high as 3%. This will give smaller components and means more planar circuit components can be produced from a single wafer.

The company does not plan to license its technology - it plans to ship components at the wafer level to optical component and module manufacturers.

Author
Nadya Anscombe is editor of Optics.org and Opto & Laser Europe magazine.