Over the recent years, optical wireless technologies have been incorporated into millions of products such as televisions and mobile phones, enabling last-mile broadband access, inter-satellite links, and deep space connections. Despite its wide-ranging applications, optical wireless communication faces challenges especially when encountering a certain type of environment.
Challenges in Optical Wireless Technology
In our modern times, almost all information transmitted through various devices is digital. The truth, however, is that images, sounds, and data are inherently analogue. Digitization enables complex processing, but as the volume of data increases, such operations become less sustainable in terms of energy and computation. Recently, there has been a great interest in returning to analogue technologies using dedicated circuits that serve as enablers for the future 5G and 6G wireless interconnection systems.
Analogue computing can be carried out using optical processors and is crucial in scenarios that include artificial intelligence, positioning and sensor systems, advanced localization, and high-performance computing (HPC). It is also applicable in neuromorphic systems, quantum computers, and cryptography. In general, analogue computing is needed by all systems that require very high speed in processing of enormous amounts of data.
Light is known for being sensitive to any form of obstacle, even very small ones. This challenge is also encountered by a beam of light that carries data streams in optical wireless systems. Although the information is still present, it is completely distorted and extremely difficult to retrieve.
Removing the Communication Barrier
A team of scientists from the University of Glasgow and Stanford University has claimed that optical wireless technology may no longer encounter obstacles. Led by Politecnico di Milano and Scuola Superiore Sant'Anna, they created photonic chips which calculate the optimal shape of light mathematically in order to pass through any environment easily.
Using photonic processors, the researchers determine the optimal bidirectional orthogonal communication channels through arbitrary and scattering optical systems. The processors are made of meshes of electrically tunable Mach-Zehnder interferometers in silicon photonics. The configuration can be made by the meshes based on simple power maximization or minimization algorithms, even without external calculations or any previous knowledge of the optical system. The identification of the communication mode channels corresponds to a singular value decomposition of the entire optical system which was performed autonomously by the photonic processors.
The devices developed in this study are small silicon chips which serve as smart transceivers. As they work in pairs, the chips automatically and independently calculate the shape that a beam of light should take in order to gain maximum efficiency while passing through a generic environment.
The devices can also generate multiple overlapping beams and direct them without interfering with each other. This way, the capacity of transmitting information is increased, just as required by next-generation wireless networks.
According to Morichetti, their chips are mathematical processors which calculate light with almost no energy consumption. Through simple algebraic operations, the optical beams are generated and transmitted by micro-antennas integrated directly on the chips. This technology provides a lot of advantages. It allows extremely easy processing of data with high energy efficiency and an enormous bandwidth that exceeds 5000 GHz.
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