A novel microwave signal generator could aid in the advancement of wireless communication, imaging, atomic clocks, and other fields.
Frequency combs are photonic devices that generate a comb-like shape by producing multiple equally spaced laser lines, each locked to a specific frequency. They can be used to generate high-frequency, steady microwave signals, and scientists are working to miniaturize the method so that it may be utilized on microchips.
Scientists’ ability to modify these microcombs at a rapid enough rate to make them useful has been hampered. However, in Nature Communications, a team of researchers led by Qiang Lin, professor of electrical and computer engineering and optics at the University of Rochester, described a new high-speed tunable microcomb.
“One of the hottest areas of research in nonlinear integrated photonics right now is trying to produce this kind of frequency comb on a chip-scale device,” Lin explains. “We are very excited to have developed the first microcomb device that produces a highly tunable microwave source.”
The device is a lithium niobate resonator that allows users to alter bandwidth and frequency modulation rates orders of magnitude quicker than current microcombs.
“The device provides a new approach to electro-optic processing of coherent microwaves and opens up a great avenue towards high-speed control of soliton comb lines, which is critical for many applications including frequency metrology, frequency synthesis, RADAR/LiDAR, sensing, and communication,” says Yang He, the paper’s first author and an electrical and computer engineering postdoctoral scholar in Lin’s lab.
