New manufacturing process promises improved chip economics

A new manufacturing process could significantly reduce the cost and time required to create photonic chips for optical-communications applications. Chips developed with the low-temperature process, which produces waveguides on a hybrid polymer/glass material, should be available in sample quantities in the first half of next year.

Lumenon Innovative Lightwave Technology Inc. (Dorval, QC, Canada), developer of the process, has teamed with Molex Inc. (Lisle, IL) to bring components using this new style of photonic chip to market. According to Dr. Iraj Najafi, president and chief executive of Lumenon, the Photonic Hybrid Active Silica Integrated Circuit (PHASIC) process works in much the same way as printing photographs in a darkroom. The PHASIC process starts with a silicon substrate, to which is added a coating of a hybrid glass/polymer compound commonly referred to as sol-gel. A contact mask placed on top of the substrate maps the waveguides the chip will carry. Light shown onto the chip through the openings in the mask changes the refractive index of the exposed areas of the material, creating waveguides.

Dr. Najafi says that he and his colleague, Lumenon chief technical officer Dr. Mark Andrews, have constructed singlemode and multimode waveguides in a single step using the PHASIC process. In fact, they also succeeded in producing usable chips outside of a cleanroom, although Dr. Najafi says that cleanrooms will be standard features at Lumenon's new fabrication facility.

Lumenon touts the PHASIC process as significantly cheaper, less time consuming, and more flexible than such chip manufacturing methods as flame hydrolysis and ion exchange. The PHASIC method also requires lower temperatures than these techniques--around 100°C to 150°C, compared to as much as 1000°C for flame hydrolysis and 500°C for ion exchange.

This low-temperature requirement will enable Lumenon to produce both active and passive components using the process, Dr. Najafi says. The ability to adapt the sol-gel material for different applications also enhances the process's flexibility, he adds.

Molex plans to take full advantage of the PHASIC method. "We're looking at Lumenon to provide basically the wave guide array technology for a variety of components," explains Molex marketing vice president Xavier Clairardin, who is expected to hold a seat on Lumenon's board of directors.

Clairardin expects the first products will be "branching elements" for dense wavelength-division multiplexing (DWDM) applications. Sample quantities of these components should be available by the second quarter of next year, he predicts, with the components released for full production in the following quarter.

While Dr. Najafi declined to quantify the price and time savings offered by the PHASIC method, Clairardin expects significant results. "I would say we are looking at cutting costs in half in terms of some of those components out there," he says. This cost reduction derives not only from the PHASIC process but from Molex's passive alignment packaging techniques as well.

Molex has an exclusive relationship with Lumenon for use of the technology for approximately two more years, says Clairardin. The future of the partnership beyond that time period remains a matter of speculation, although Dr. Najafi indicated that Lumenon has aggressive expansion plans.

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