Physicists at the University of Bath in the UK have developed a new generation of specialty optical fibers to address the future challenges of data transfer in the quantum computing era.

Figure 1. Glowing Optical Fibres. (Credit: Cameron McGarry)

Quantum technologies hold the promise of unmatched computational power, enabling the solution of complex problems, the development of new medicines, and the provision of unbreakable cryptographic techniques for secure communications. However, the current cable networks used for global information transmission may be suboptimal for quantum communications due to the solid cores of their optical fibers. Figure 1 shows bright light guided through an optical fibre manufactured at the University of Bath [1].

Unlike standard optical fibers, the specialty fibers created at Bath feature a micro-structured core with a complex pattern of air pockets running along the fiber's entire length.

Dr. Kristina Rusimova from Bath's Department of Physics explained, “The conventional optical fibres that are the workhorse of our telecommunications networks of today transmit light at wavelengths that are entirely governed by the losses of silica glass. However, these wavelengths are not compatible with the operational wavelengths of the single-photon sources, qubits, and active optical components, that are required for light-based quantum technologies.” [2]

In an academic paper published in Applied Physics Letters Quantum, Dr. Rusimova and her colleagues discuss the state-of-the-art fibers made at Bath, along with other recent and future developments in quantum computing. As the lead senior author of the paper, Dr. Rusimova added, “Optical-fibre design and fabrication is at the forefront of the University of Bath Department of Physics research, and the optical fibres we are developing with quantum computers in mind are laying the foundations for the data transmission needs of tomorrow.”

Light, with its uniquely quantum properties, is a promising medium for quantum computation. Quantum entanglement, where two photons separated by a large distance hold information about each other and can influence each other’s properties instantaneously, is one example. Unlike classical computers' binary bits, pairs of entangled photons can exist as both a one and a zero simultaneously, unlocking enormous computational power.

Dr. Cameron McGarry, a former physicist at Bath and first author of the paper, emphasized, “A quantum internet is an essential ingredient in delivering on the vast promises of such emerging quantum technology. Much like the existing internet, a quantum internet will rely on optical fibres to deliver information from node to node. These optical fibres are likely to be very different to those that are used currently and will require different supporting technology to be useful.”

The researchers discuss the challenges of the quantum internet from the optical fiber technology perspective and propose potential solutions for scalable, robust, wide-scale quantum networks. This includes fibers for long-range communication and specialty fibers that enable quantum repeaters, integrated into the network to extend its operational distance.

They also explore how specialty optical fibers can implement quantum computation at the network nodes, acting as sources of entangled single photons, quantum wavelength converters, low-loss switches, or vessels for quantum memories.

Dr. McGarry noted, “Unlike the optical fibres that are standardly used for telecommunications, speciality fibres which are routinely fabricated at Bath have a micro-structured core, consisting of a complex pattern of air pockets running along the entire length of the fibre. The pattern of these air pockets is what allows researchers to manipulate the properties of the light inside the fibre and create entangled pairs of photons, change the colour of photons, or even trap individual atoms inside the fibres.”

Dr. Kerrianne Harrington, a postdoctoral researcher in the Department of Physics, added, “Researchers around the world are making rapid and exciting advancements in the capabilities of microstructured optical fibres in ways that are of interest to industry. Our perspective describes the exciting advances of these novel fibres and how they could be beneficial to future quantum technologies.”

Dr. Alex Davis, an EPSRC Quantum Career Acceleration Fellow at Bath, highlighted, “It's the ability of fibres to tightly confine light and transport it over long distances that makes them useful. As well as generating entangled photons, this allows us to generate more exotic quantum states of light with applications in quantum computing, precision sensing and impregnable message encryption.”

While quantum advantage—the ability of a quantum device to outperform a conventional computer—has yet to be conclusively demonstrated, the technological challenges identified in the perspective are likely to open new avenues of quantum research and bring us closer to achieving this milestone. The optical fibers developed at Bath are expected to lay the groundwork for future quantum computers.

The research team at Bath also included senior lecturer Dr. Peter Mosely.

Source: University of Bath

References:

1. https://www.eurekalert.org/news-releases/1052584
2. https://phys.org/news/2024-07-optical-fibers-age-quantum.html

Cite this article:

Hana M (2024), University of Bath Develops Specialty Optical Fibers for Future Quantum Computing Challenges, AnaTechMaz, pp. 148