Efficient entanglement routing in Quantum Data Networks (QDNs) is essential in order to concurrently establish as many Entanglement Connections (ECs) as possible, which in turn maximizes the network throughput. In this work, we consider a new class of QDNs with wavelength division multiplexed (WDM) quantum links where each quantum repeater will perform entanglement swapping by measuring two photonic qubits coming from some entangled photon sources directly on the same wavelength. To address unique challenges in achieving a high network throughput in such QDNs, we propose QuRWA to jointly optimize the entanglement routing and wavelength assignment. To this end, we introduce a key concept named Co-Path to improve fault-tolerance: all ELs in a Co-Path set will be assigned the same wavelength and this may serve as backup for some other ELs in the same Co-Path when establishing ECs. We design efficient algorithms to optimize the Co-Path selection and wavelength assignment to maximize resource utilization and fault tolerance. Extensive simulations demonstrate that compared with the methods without introducing Co-Path, QuRWA improves the network throughput by up to 122%.

Quantum Data Networks (QDNs) are vital to building Distributed Quantum Computing (DQC) systems. Though several communication protocols have been proposed for QDNs, most of them are at the network layer or below. The only transport layer protocol [1] used batch processing of requests for End-to-End (E2E) quantum data transmission. It not only limits the quantum resource utilization, more importantly, it cannot guarantee reliable E2E quantum data transmission. In this paper, we propose the first asynchronous transportation layer protocol, called AQTP, for QDNs to achieve high-speed and reliable E2E quantum data transmission. AQTP has several distinct features: (i) each quantum node locally allocates quantum resources in order to improve scalability; (ii) requests are processed in an asynchronous manner, which results in a higher quantum resource utilization; and (iii) it ensures reliable data transmission even if the teleportation operations fail. Extensive simulations show that compared with a batch processed transport layer protocol, AQTP can increase the network throughput by up to 82.97%, and reduce the Average Task Completion Time (ATCT) of DQC tasks by up to 94.69%.