US AFRL approves cooperative R&D agreement for silicon photonics

12 Apr 2021

Nanoelectronic Materials branch and Iris Light Tech startup to work together on hybrid “printable” silicon lasers.

The US Air Force Research Laboratory has approved a cooperative Research and Development Agreement between its Nanoelectronic Materials Branch and Iris Light Technologies, an on-chip laser technology startup.

The collaboration will be working to develop hybrid silicon lasers. Iris Light is an Argonne National Lab spinout, based in Chicago, IL, and currently incubating in the Chain Reaction Innovations program funded by the US Department of Energy.

AFRL research scientist Dr. Steven Mckeown is part of a team that is investigating silicon photonics with a goal of finding a better way to fabricate hybrid devices that make possible the integration of lasers onto silicon chips. “The problem is that silicon has poor optical gain, gain being how we get lasing,” he said.

Part of the challenge is to find a less expensive and more reliable way to manufacture on-chip lasers, as well as a way to enable their mass-production. One method AFRL is investigating involves a type of photonic ink developed by Iris Light, AFRL’s partner in the cooperative research agreement (CRADA).

With this particular CRADA, Iris Light will provide AFRL with a set of test chips.

Using the photonic ink, Iris Light prints laser gain material directly onto passive silicon chips. The firm is aiming to modify the ink so that it will emit light when it is pumped by electric current; the ink can emit light over a broad spectrum – from visible to the near infrared.

“The ink is what converts the energy into the laser light,” said McKeown. “The component that shapes the light and guides it is the silicon. That interacts with the ink and converts energy into the laser emission.”

‘Many applications’

Such nano-material lasers could have many practical applications, say the partners. For example, one notable use would be in the circuitry of computers. “This development is especially relevant for data processing centers that use insane amounts of power,” said McKeown.

“Interconnects now use pluggable transceivers to put data onto an optical fiber to move from rack to rack. The more tightly we can integrate all these pieces, the closer they get and the shorter the wires we need. The best case is a silicon photonic chip complete with a laser and the CMOS circuitry all in one,” he added.

Other applications of special interest to AFRL are hyperspectral sensing, Light Detection and Ranging (LIDAR), and radio frequency (RF) photonics.

McKeown added that getting lasers on a silicon platform is an ongoing challenge. “Researchers are looking at everything, and not every solution may apply to every problem. We may end up with a toolkit that has several solutions, or we may end up with one solution for all problems.”