Researchers at the Harvard University's John Paulson School of Engineering and Applied Science (SEAS) have completed their first experiments with semiconductor lasers to send and receive radio signals. This hybrid optoelectronic device uses lasers to extract and transmit microwave signals, paving the way for one-day ultra-high-speed Wi-Fi data transmission technology.
In this trial, the research team selected Dean Martin's "Volare" song. Although the use of radio to transmit audio has long been nothing new, but with the qualifier of "laser", the meaning is completely different.
According to the research team, the laser can not only transmit wireless microwaves, but also receive external radio signals through modulation.
In the research work carried out in 2017 and 2018, the team has tried radio communication in the infrared laser spectrum.
This single-frequency laser is like a note played by the violin, rather than white noise covering the entire spectrum.
The beam that the laser can produce is closely related to the optical frequency comb (OFC) component (the light is evenly spaced like a comb).
Interestingly, in 2018, the SEAS team discovered that the "optical teeth" of the optical frequency combs were able to resonate with each other, causing the electrons in the laser cavity to oscillate at the frequency of the microwave in the no-wire band of the spectrum.
In the top electrode of the device, there is an etched slot as a dipole antenna, similar to the 'rabbit ear' on an analog TV set.
Through modulation, the team is able to encode the microwave transmit data and then send it to the receiving point via the antenna. After being picked up by the horn antenna, the computer can filter and decode it.
In addition, laser technology can also be used to receive radio signals and to support remote control of the behavior of the lasers through the microwaves of the second device. SEAS researcher Marco Piccardo said:
Although there is still a long way to go before THz radio communication, this all-in-one integrated device brings great hope for the future of radio communication.
This research has provided us with a clear road map showing how this can be achieved.
Finally, details of the study have been published in the recently published Proceedings of the National Academy of Sciences.