This program develops new measurement techniques, tests and performance procedures, standards, and best practices to enable industry and government to gain confidence in this new disruptive network technology: quantum optical network technology. Harnessing quantum networking technologies will power our economic competitiveness and provide better communication security.
Entangled photons’ stability and their distribution are fundamental steps for quantum networking to succeed. Today, entanglement is fragile and easily degraded during its transmission, processing, or storage. The quantum networking program research will address the core problem of entanglement distribution and stability by developing efficient and resilient protocols stacks to identify, distribute, manage and manipulate entangled photons and propose solutions that overcome environment-induced optical and quantum impairments such as destruction of their coherence.
This program will focus primarily on Quantum Networking Protocols design and their performance evaluation and pre-standardization validation. It will also undertake collaborations with NIST partners in CTL, ITL, and PML to design, program, and carry out experiments to collect network metrics for control plane performance evaluation. To achieve its goal, the program favors prototype systems that have been developed for remote operation or commercial systems.
The program's technical research areas are:
The fundamental limitations to quantum entanglement distribution will be investigated through the design of local and regional quantum optical networks with quantum nodes while the feasibility of large-scale quantum networking (Quantum Internet) will be explored through simulations.
This program will study innovative architectures for quantum optical nodes and networks that will enable co-existence of classical and quantum channels across the network. The architecture study will inform about the potential and limitations of using fiber switching, wavelength/waveband switching and quantum label switching technologies and their scalability.
The first attempt will study circuit-switching dynamic optical networks to interconnect several quantum sources and several quantum detectors using passive optical switching based on fiber cross-connects and Wavelength Selective Switches (WSS) modules. The second attempt will investigate quantum optical label switching a mechanism to switch a payload that carries a classical header (bits) followed by quantum data (qubits) all in a single quantum packet. The quantum transmitter builds the quantum packet with the right classical header. Using the classical information in this header, the packet is switched and routed at each intermediate network node until it reaches its destination where it is then delivered to a quantum receiver which will strip the header and deliver the quantum data to a quantum detector. This approach, called Optical Label Switching (OLS), was previously researched in the context of transparent optical networks, but never endorsed by the industry. Future investigations will include quantum memories and processors as they become available. Installing new dark fibers for transmitting quantum information separately from the classical information is a high-cost approach. To include classical traffic, multiplexing systems that allow the transmission of qubits for example at the telecom O-band with classical traffic at the telecom C-band over the same optical fiber without generating severe background noise at the quantum channel will be investigated.
Management, Control, and Measurement Planes for Quantum Optical Networks:
The program will develop a scalable Quantum Control Plane that will signal and route entangled photons according to the selected architecture across the network to quantum end-nodes (receivers). The quantum routing will have metrics based on quantum channel tomography collected by metrology nodes and frequency conversion availability at certain nodes – an approach similar to wavelength conversion in today’s optical networks. The centralized Software Defined Networking (SDN) approach and distributed control will be investigated and contrasted.
The management plane will be based on digital twin technology to capture information from the design, build, and operating cycle of the Platform for Quantum Network Innovation testbed.
A measurement plane will be developed in collaboration with our PML, ITL, and CTL partners to allow experimenters to carry network measurements and collect results that will be selectively archived, analyzed using Machine Learning, and fed back to the digital twin. The measurement plane design is based on the tuple (capability, specification, result). Capabilities are the type of measurements available on the network. They will be realized with hardware or software probes deployed in the network and registered and managed by the management plane. Specifications carry parameters for specific capabilities that are sent to probes to carry a measurement. This is a way for experimenters to program the probes for specific measurements. The specifications are executed by the measurement plane at the specified probes. Results will be collected and sent back to experimenters all within the measurement plane. Depending on the nature of the probes, several experiments could be launched in parallel.
The measurement plane will also be used by specialized network functions that are part of the infrastructure such as network stability and network synchronization to deliver critical data necessary to the health of the network.
Design of Entanglement Distribution Protocols:
Both centralized and distributed entanglement distribution protocols over several network topologies will be investigated and their complexity will be assessed by mathematical analysis, simulated using quantum network simulators, and prototyped and deployed in the PQNI and DC-QNet testbeds.
Precision network synchronization and accurate time stamping across the control plane will be developed to provide stability control of the quantum data plane.
The program includes the development of a local area quantum network in the Gaithersburg campus (PQNI) and also participates in the buildup of a regional government testbed in the Washington DC area (DC-QNet). As one of its milestones, the program will develop a control plane software that will be deployed and evaluated on PQNI and DC-QNet.