Compact telecoms light amplifier demonstrates higher gain

1 min read

A high gain optical amplifier that is compact enough to be placed on a chip has been created by researchers at the Singapore University of Technology and Design (SUTD), A*STAR Data Storage Institute and the Massachusetts Institute of Technology.

The developed amplifier, when used within an optical interconnect, such as a transceiver or fibre optic network, could potentially help to increase the power of the transmitted light before it is depleted through optical losses.

"We have developed an optical amplifier which can amplify light by 17,000 times at the telecommunications wavelength," said assistant professor Dawn Tan at SUTD.

"We use a proprietary platform called ultra-silicon-rich nitride, with a material composition of seven parts silicon, three parts nitrogen, with the large nonlinearity and photon efficiency needed for high gain amplification, through the efficient transfer of photons from a pump to the signal,” she explicated.

The device offers cascaded four wave mixing, which allows the amplifier to operate as a tuneable broadband light source, enabling cheaper and more efficient spectroscopic sensing and molecular fingerprinting.

"The inefficiencies in highly nonlinear photonic devices are overcome here, by photonic device engineering for maximum nonlinearity, while still maintaining a sufficiently large bandgap to eliminate two-photon absorption at the telecommunications wavelength,” explained Prof Tan.

“We believe this is one of the highest gains demonstrated at the telecommunications wavelength to date on a CMOS chip,” she concluded.

According to the researchers, providing high gain on such a small footprint could enable new opportunities in low cost broadband spectroscopy, precision manufacturing and hyperspectral imaging.