Researchers Create a Wireless Chip With Data Rates Faster than 5GAugust 10, 2020 by Jake Hertz
The new chip leverages photonic topological insulators to operate in the terahertz band—not in the 5G range, but in the 6G range.
Without 5G even fully realized, researchers are already making the push toward 6G. New generations of mobile communication may require Tbps speeds, which far exceed the theoretical capacity of 5G at 10 Gbps.
As it stands right now, researchers feel that the key to 6G is finding ways to operate in the previously unoccupied terahertz band. Now, researchers at Nanyang Technological University in Singapore and Osaka University have developed a wireless chip to operate in this band.
What is the Terahertz Band?
As Dr. Neda Khiabani explains in his AAC article, terahertz (THz) radiation is generally defined as the region of the electromagnetic spectrum in the range of 100 GHz (3 mm) to 10 THz (30 μm). Compared to its neighboring microwave and optical bands, this portion of the EM spectrum is considerably understudied.
The electromagnetic spectrum. Image used courtesy of Dr. Neba Khiabani
According to Yihao Yang et al., researchers pushing for 6G are now extremely interested in this band since the THz spectral region offers a higher available bandwidth, which could meet the ever-growing demand for higher data transfer rates.
It’s also speculated that the THz spectral band may be used to address the interconnect tradeoff between high-speed, energy-efficiency, and low-cost intrachip/interchip communication links. This can help designers tap into massive multicore processors, networks-on-chips, or system-in-package solutions.
Challenges of Working in the Terahertz Band
While the terahertz band seems to offer some incredible potential, it does not come without its drawbacks. There are many challenges involved with developing in the THz band. Two of the biggest issues are the material defects and transmission error rates found in conventional waveguides such as crystals or hollow cables.
Terahertz wave atmospheric power attenuation. Image used courtesy of John F. Ohara et al.
These problems become paramount in this higher-frequency band since shorter wavelengths mean greater attenuation and more sensitivity to material defects in the waveguide. Current approaches suffer from sensitivity to defects such as fabrication imperfections and considerable bending losses at sharp corners.
A New Wireless Chip for the THz Band
Scientists from Nanyang Technological University in Singapore and Osaka University in Japan have recently announced new work that may overcome these aforementioned issues.
The researchers utilized a technology called photonic topological insulators (PTIs) in order to lessen the effects of attenuation in terahertz waveguides. PTIs are said to be “'insulating’ in bulk but ‘conducting’ at the edges" which shows "robust edge transport with strongly suppressed backscattering caused by disorder and sharp bends.”
Researchers with a terahertz chip utilizing PTIs. Image used courtesy of NTU Singapore
In simpler terms, PTIs allow light waves to be conducted on the surface and edges of the insulators, rather than through the material. In this way, terahertz waves can be redirected around sharp corners and its flow will resist being disturbed by material imperfections.
Exceeding 5G Speeds
By using PTIs, the researchers were able to successfully create an all-silicon chip that could transmit signals error-free while routing THz waves around 10 sharp corners at a rate of 11 gigabits per second, bypassing any material defects that may have been introduced in the silicon manufacturing process. This speed of 11 Gbps in itself already surpasses the theoretical maximum of 5G, which is 10 Gbps.
Researchers hope their work will pave the way for future PTI THz interconnects with sights set on 6G deployment.
Associate Professor Ranjan Singh says, “With the 4th industrial revolution and the rapid adoption of Internet-of-Things (IoT) equipment, including smart devices, remote cameras, and sensors, IoT equipment needs to handle high volumes of data wirelessly, and relies on communication networks to deliver ultra-high speeds and low latency."
He continues, "By employing THz technology, it can potentially boost intra-chip and inter-chip communication to support artificial intelligence and cloud-based technologies such as interconnected self-driving cars, which will need to transmit data quickly to other nearby cars and infrastructure to navigate better and also to avoid accidents.”