November 27, 2022

A quantum memory that operates at telecom wavelengths

Researchers at Delft University of Technology (TU Delft) have developed a new mechanical quantum memory with sufficiently long storage times, a high readout efficiency, and the ability to operate at telecom wavelengths. 

As key component of quantum repeaters, the main enablers of a future quantum Internet, quantum memories (QRAM) are the quantum-mechanical equivalents of more conventional computer memories, such as random-access memories (RAM).

Ideally, a quantum memory should be able to retain information for substantial periods of time, store true quantum states, read out data efficiently and operate at low-loss telecommunication wavelengths.

The quantum memory devised the team has several advantageous characteristics. One of the main ones is that it is fully engineerable, which means that the optical wavelengths at which it operates are selectable, as the system’s optical and mechanical resonances are fully artificial. The researchers designed them using a computer and then fabricated the device accordingly.

While many previously developed quantum memories achieved promising results, very few of them were able to operate at telecom wavelengths (around 1550 nm), which are essentially the wavelengths at which all telecommunication takes place over long distances. Moreover, memories that were able to operate at these wavelengths were either very complex or had extremely short lifetimes.

This QRAM is still a proof of concept, but its performance is very promising. (

The paper has been published in Nature Physics.

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