2021-06-09

Toshiba breaks 600km optical fiber quantum communication record

By yqqlm yqqlm

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Toshiba breaks 600km optical fiber quantum communication record

Data map (from: Toshiba official website)

For example, last year, the domestic nine chapter quantum computer A calculation that would take 2.5 billion years to complete for an ordinary supercalculation was completed in 200 seconds.

However, the bigger challenge of quantum computing is that qubits are very sensitive to environmental interference. Even very small temperature changes or fluctuations may affect the validity of data, which means that long-distance quantum information transmission is also quite difficult.

Toshiba breaks 600km optical fiber quantum communication record(1)

Research Picture-1: Experimental Device< /p>

The good news is that in an article recently published in the journal Nature Photonics, the Toshiba research team has introduced the new distance record they set for quantum communication through optical fiber.

The key to the success of the experiment lies in the so-called “dual band stability” new technology developed by it. On the basis of the qubit, it will also send two optical reference signals.

Toshiba breaks 600km optical fiber quantum communication record(2)

Research picture-2: Dual frequency stability Scheme

These signals are encoded as the phase delay of weak light pulses, among which the wavelength of the first reference signal is designed to offset environmental disturbances. The working wavelength of the second reference signal is the same as that of the qubit itself to precisely control the phase of light.

Based on this, the Toshiba team was able to maintain quantum signals within a few tens of nanometers, and instead allowed them to transmit data over 600 kilometers of optical fiber – six times the previous record.

Toshiba breaks 600km optical fiber quantum communication record(3)

Research Picture-3: Critical Rate Simulation And results

Although this is not the longest quantum information transmission record that has been achieved so far, because satellite transmission still tops the list with the advantage of 1,200 kilometers (746 miles), the quantum Internet still needs to cooperate with satellites/ Mixed use of optical network.

The team pointed out that this technology may be the first to be used for quantum key distribution (QKD for short). Thanks to the strange rules of quantum physics, this encryption technology can cause behavior changes when observed by a third party, allowing users to be more vigilant and useless to potential hackers.

Toshiba breaks 600km optical fiber quantum communication record(4)

Research Picture-4: Qubit Extraction

Andrew Shields, head of Toshiba’s European Quantum Technology Department, said: “In recent years, quantum key distribution has been used for the protection of metropolitan area networks.”

This latest development further expands the maximum span of quantum links, helping to achieve transmission across cities, countries, and even continents without the need for trusted intermediate nodes. By implementing it together with the satellite QKD program, the new program will help us build a secure network based on quantum communication on a global scale.