Wireless optical communication LiFi is a method of transmitting data rates over short distances. However, the sun and other light sources can interfere with this transmission. One possible way to prevent this from happening is to use deep ultraviolet LEDs for transmission because they operate at a "solar blind" wavelength, meaning that the sun's light is scattered when it reaches the earth's surface in the deep ultraviolet, and data transmission using deep ultraviolet LEDs will not be interfered with by the sun or other light sources.
Based on this, researchers at Tohoku University in Japan have proposed a method to enhance LiFi for optical wireless communication using deep ultraviolet LEDs, and published their research results in Applied Physics Letters on July 22.
Kazunobu Kojima, associate professor at the Multidisciplinary Institute for Advanced Materials at Tohoku University, said that both visible and infrared light wireless communication can be significantly interfered by sunlight. To avoid visible and infrared light being confused by sunlight, the researchers aim to improve optical communication through deep ultraviolet light, which is not interfered with by sunlight and can be detected.
Kojima said: deep ultraviolet LEDs have now been mass-produced by manufacturers for applications with COVID-19 extinction. So applying deep UV LEDs to optical communications to avoid interference from sunlight would be a cheap and practical option.
In addition, Kojima said: a key technology for fast modulation is to reduce the device size. However, this strategy creates a dilemma: "While smaller LEDs can be modulated faster, they have lower power.In response, the researchers fabricated deep-UV LEDs on sapphire templates and measured their transmission speeds. They found that deep-ultraviolet LEDs are smaller and communicate faster than conventional LEDs.
The mechanism for this speed lies in the fact that a single deep-ultraviolet LED is an array of many small LEDs integrated, Kojima said. The integration of small LEDs helps boost the power and speed of optical communication technology.
Kojima said: LiFi is one of the candidate technologies applied to 5G, hope to use deep ultraviolet LEDs in 5G wireless networks to compensate for the weakness of LiFi technology, weakening the interference of sunlight on LiFi function.
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