Researchers transmit data via semiconductor laser, paving the way for ultra-fast Wi-Fi

You have never heard Dean Martin like that.

Researchers at the Harvard School of Engineering and Applied Sciences John A. Paulson wirelessly transmitted a recording of Martin's classic "Volare" via a solid-state laser – the first time that it was used. a laser was used as a radiofrequency transmitter.

In an article published in the Proceedings of the National Academy of Sciences, the researchers presented a laser capable of emitting wireless microwaves, modulating them and receiving external radio frequency signals.

"The research opens the door to new types of electro-electronic hybrid devices and is the first step towards ultra-fast Wi-Fi," said Federico Capasso, professor of applied physics at Robert L. Wallace, and principal investigator. to Vinton Hayes. in Electrical Engineering, at SEAS and lead author of the study.

This research is based on the previous work of the Capasso laboratory. In 2017, researchers discovered that an infrared frequency comb in a quantum cascade laser could be used to generate terahertz frequencies, submillimetric wavelengths of the electromagnetic spectrum that can move data hundreds of times faster than today's wireless platforms. In 2018, the team discovered that quantum cascade laser frequency combs could also serve as integrated transmitters or receivers to efficiently encode information.

Researchers have now found a way to extract and transmit wireless signals from laser-frequency combs.

Unlike conventional lasers, which emit a single light frequency, the laser frequency combs simultaneously emit several frequencies, evenly spaced to resemble the tooth of a comb. In 2018, researchers discovered that inside the laser, the different frequencies of light were mixed to generate microwave radiation. The light inside the laser cavity caused the oscillation of electrons at microwave frequencies, which are part of the communication spectrum.

"If you want to use this device for Wi-Fi, you need to be able to insert useful information into the microwave signals and extract them from the device," said Marco Piccardo, a postdoctoral fellow at SEAS and the author's first author. 39; section. .

The first thing the new device needed to transmit microwave signals was an antenna. The researchers then etched a space in the upper electrode of the device, creating a dipole antenna (like the rabbit ears above an old TV). Then, they modulated the frequency comb to encode information on the microwave radiation created by the flapping comb light. Then, using the antenna, the microwaves are emitted by the device and contain the coded information. The radio signal is received by a horn antenna, filtered and sent to a computer.

The researchers also demonstrated that laser radio can receive signals. The team was able to remotely control the laser's behavior using microwave signals from another device.

"This all-in-one integrated device is very promising for wireless communication," Piccardo said. "Although the dream of wireless terahertz communication is yet to be found, this research provides a clear roadmap of how to achieve it."

The Harvard Technology Development Office has protected the intellectual property associated with this project and is exploring marketing opportunities.