The invention of a polarizing technology to transform our windows and the sun’s rays into a wireless network

In recent years, we have witnessed a phenomenal development in data transmission technologies. This time around, researchers at King Abdullah University of Science and Technology in Saudi Arabia have discovered a way to harness natural light streaming through a window to transmit data. In concrete terms, they have designed smart glass capable of modulating the sun’s rays. Data is encoded through light and then decoded by devices in the room.

DLS, a low-power wireless technology

The wireless communication system developed by the KAUST team comprises two devices: a light modulator integrated into the glass and a receiver (located in the room). According to the explanations ofOsama amin, a researcher at Shihada Laboratories, the modulator features transparent components known as Dual-cell Liquid Crystal Shutters (DLS). This set of shutters acts as a filter by encoding signals in light. What is also interesting is the fact that the operation takes place at very low power, around 1 Watt. The energy needed to power the system can therefore be provided by a small solar panel. For information, Wi-Fi generally consumes ten watts or more.

Illustration of the polarizer effect on light. Image credit: IEEE Photonics Journal (2022). DOI: 10.1109/JPHOT.2022.3200833

Better than Li-Fi?

We know that Li-Fi (a wireless communication technology based on the use of visible light) encodes data in the intensity of the light emitted. DLS, on the other hand, change the polarization of light passing through them. We cannot perceive this modification with the naked eye… The receiver in turn detects this change and decodes the data transmitted.

I was just hoping to use a cell phone camera to record video of the encoded light stream to try to decode the video to retrieve the data; that’s when I thought, why not do the same with sunlight? (…) It would be much easier and it could also be done via the mobile phone camera. So we started to explore sunlight as an information carrier (…) The modulator is an array of smart glass elements that we have come up with, known as dual-cell liquid crystal shutters ( DLS) (…) The liquid crystal shutter array, which would act as a filter to encode the signals in the light as it passed, would only require 1 watt of power to operate, which can be supplied by a small panel solar. In previous designs of wireless optical communication systems, data was usually encoded by varying the intensity of light (…) But if the frequency of these intensity variations is too low, it can be detected by the human eye and cause an uncomfortable flickering effect.Basem Shihada

Flow rate still low

According to the team, this technology should make it possible to transmit data at a speed of 16 kbit/s. A test bench prototype will soon be available. Researchers aim for increased throughput from kilobits to megabits, even gigabit per second. Unfortunately, the main disadvantage of this technology is that it only works during the day. At night, it will therefore be necessary to return to conventional Wi-Fi or to the transmission of cellular data…

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