Just as 5G telecom is being rolled-out, researchers are already busy developing 6G technology. Nature Communications just reported on a new waveguide that could revolutionize terahertz signal transmission and processing. Data streams in the terahertz spectral region could meet the ever-growing demand for unprecedented data transfer rates since it offers a higher available bandwidth. However, at terahertz frequencies, it is extremely challenging to develop physical components that go beyond the most elementary processing functionalities required by future communication systems.
But now, team of researchers has developed a new waveguide to overcome those limitations. The scientists designed a novel approach for the realization of broadband terahertz signal processing in metal-wire waveguides by engineering the wire surfaces.
These act like pipes for electromagnetic waves and confine their propagation. The researchers demonstrated that, by engraving judiciously designed grooves with multiscale structures, called Bragg gratings, directly onto the metal-wires, they could change which frequencies were reflected or transmitted without adding any material to the waveguide.”
The new design exploits this concept for the first time in the terahertz region. It allows for unprecedented flexibility towards manipulating terahertz pulses propagating within the waveguides, which in turn enables more complex signal-processing functionality. For example, the researchers foresee the use of “holographic messaging” in 6G, analogous to SMS and voice mail in 1G and 2G. Besides transporting the data streams, innovative terahertz waveguides can provide versatile signal-processing functionalities.
The distinct advantages of metal-wire waveguides, including structural simplicity, tolerance to bending and similarity to cables for connections, make them very promising. As a proof of concept, the researchers introduced a completely new waveguide geometry: the four-wire waveguide which is capable of sustaining two independent waves that are vertically and horizontally polarized, so they do not interfere with each other. This design pioneers, for the first time, polarization-division multiplexing in terahertz waveguides.
In other words, it allows the two channels of information to be transmitted over a single transmission path. Most importantly, by integrating the Bragg gratings with the engraving, they can be manipulated independently.
This device represents the first terahertz waveguide architecture, with a new metal-based design, which supports polarization-division multiplexing. In particular, the capability of realizing independent manipulation of multiplexed terahertz signals, has been achieved for the first time. This universal approach for the realization of broadband terahertz signal processing, in combination with novel waveguide designs, paves the way for 6G networks. It will allow for new application scenarios, such as the multi-channel transmission of uncompressed ultra-high-definition video, ultra-high-speed short-distance data transfer between devices, and chip-to-chip communications.