All-Optical Frequency Shifter Demonstrated

As the demand for speed and bandwidth in communications networks increases, new approaches to switching and routing are under study. Now researchers at the University of Illinois at Urbana-Champaign have developed an all-optical device that rapidly and accurately shifts the frequency of optical data in return-to-zero format between channels.

At the heart of the shifter, which they described at the March meeting of the American Physical Society in Austin, Texas, is a standard optical phase modulator that has an optical waveguide diffused in a lithium niobate substrate. Applying a microwave signal to a gold electrode deposited on the substrate controls the properties of the waveguide, enabling the user to dynamically shift the frequency of optical pulses within it.