One of the challenges to creating a viable quantum internet is the inherent signal loss that photonics incurs when travelling over a fiber optic cable. The maximum length is limited to perhaps 100 kilometers or so before the signal levels become too small to detect reliably. For classical signals, this is no problem because one can put in a repeater that can regenerate the signal so it can then traverse down to the next segment. However, it is not so easy with entangled photons because of the No Cloning Theorem which states that qubits cannot be copied. However, there is a potential alternative being actively researched called a Quantum Repeater that uses quantum technology such as entanglement swapping to perform this function. Although another possibility for long distance transmission of qubits could involve satellites, a quantum repeater could have significant cost, latency, and other advantages over satellites. Almost all classical internet communications today is accomplished using terrestrial and undersea cables rather than satellites.

Qunnect is developing the technology to create a quantum repeater and last year sold the first unit of one needed component called a Quantum Memory. Other components Qunnect is developing for the quantum internet include devices that provide Quantum Photon Sources, Entanglement Swapping and Photon Decoding, Qubit Frequency Conversion, Phase and Frequency Locking, Flying Photon and Transport Compensation, and Hybrid Network Synchronization. To help continue their developments and commercialization, the U.S. Department of Energy just awarded Qunnect two SBIR grants totaling $1.85 million. These funds will support commercialization of the photon source and a second type of quantum memory.

A major advantage of the Qunnect components over others working on this technology is that they do not require extreme cooling or vacuums to operate. Another unique advantage is that their photon source generates a pair of entangled photons, one optimized for fiber transmission and the other optimized for use in a quantum memory, eliminating the need for a separate frequency conversion device.

More information about this award can be seen in a press release provided by Qunnect that can be accessed here.

May 23, 2022