Caltech engineers achieve fiber-optic-level light transmission on silicon chips

Scientists at the California Institute of Technology created on-chip waveguides using germano-silicate, the same glass found in optical fibers, and adapted the material to standard lithography processes. By winding the waveguides into spirals on 8- and 12-inch wafers, they achieved loss levels near those of fiber optics, with a twenty-fold advantage over silicon nitride at visible wavelengths. The low loss dramatically improves laser coherence and enables compact atomic clocks, gyroscopes, and quantum devices.

The researchers demonstrated ring resonators, various lasers, and nonlinear resonators built from the new platform. Funding came from DARPA, the Air Force Research Laboratory, the UK Engineering and Physical Sciences Research Council, and Caltech’s Kavli Nanoscience Institute.