This course is for graduate engineers wishing to understand the role and design principles of quantum communication systems and networks, which are anticipated to be key technologies of the 21st century to address post-quantum security and support the development of the Quantum Internet. Upon successful completion of the course, the students will understand the key concepts and technologies underlying the design and performance of quantum communication links and networks by leveraging currently available simulation tools. The course will first introduce the key concepts of classical optical communication networks and review the key principles of quantum physics that form the foundations for quantum optical networks. It will then present the key concepts and related implementation schemes and challenges for emerging quantum realm applications and technologies such as quantum entanglement distribution, teleportation, entanglement swapping and routing, and quantum key distribution (QKD) networks.

After successful completion of the course, the students should have a good understanding of the physics and engineering behind the high-fidelity transmission of individual and entangled photonic quantum states over an optical communication network. The student should be able to describe, design and simulate a quantum communication system and network for quantum key distribution (QKD) and quantum entanglement distribution and teleportation. Upon successful completion of the course, each student is expected to be able to: ● Define key concepts and architectures in optical communication systems and networks (modulation formats, spectral efficiency, channel capacity and impairments, link budget and receiver sensitivity, switching architectures, routing and spectrum assignment, and software-defined open optical networks) ● Design an error-free classical optical communication system with pulse amplitude modulation (PAM) ● Explain how information encoding is done at the single-photon level and the different degrees of-freedom employed (polarization, time-bin, frequency-bin, path entanglement, etc.) ● Define key concepts and implementations of quantum communication and network devices, such as quantum sources, switches, transmission mediums, detectors ), memories, and stationary qubit-to-photon interfaces ● Define key concepts and implementations of quantum communication networks such as entanglement distribution and swapping for long-distance teleportation ● Design, simulate and analyze the performance of a quantum communication link with different source of impairments (loss, memory decoherence, crosstalk caused by copropagating classical signals over the same fiber) for entanglement distribution, swapping, and QKD applications

Linear algebra, probability theory, fundamentals of quantum mechanics, quantum information, photonic devices, Python programming language (variable declaration and types, if statements, loops, maps, Boolean logic, classes)

Classroom lessons will cover the following topics (CFUs are indicative, and variations are possible): ● Introduction to quantum communication and networks (0.2 CFU) ● Classical optical communication for quantum networks (1.6 CFU) - modulation formats, spectral efficiency, and channel capacity; linear and non-linear impairments in optical fiber systems; link budget and receiver sensitivity for IM-DD signals; switching architectures, wavelength routing and spectrum assignment; software-defined open optical systems ● Technologies and protocols for entanglement distribution networks (0.8 CFU) - Stationary qubit-to-photon interfaces; Quantum memories and repeaters; Entanglement generation, distribution and teleportation; Entanglement swapping and purification; Synchronization in quantum networks; ● Technologies and protocols for Quantum Key Distribution (0.5 CFU) - Discrete variable (DV)-QKD (Polarization, Phase, Twin Field QKD, …); Continuous variable (CV)-QKD; Trusted nodes; ● Coexistence of quantum and classical signals over the same fiber (0.3 CFU) ● Quantum packet switching (0.2 CFU) ● A series of Netsquid labs to implement and simulate the different communication and network concepts described above (1.7 CFU) ● Group projects (0.7 CFU)

The course will consist of a balanced mix of lectures and software lab sessions devoted to the design of quantum/classical communication systems and networks by leveraging existing simulation tools (e.g., Netsquid, QuREBB). The course will also make use of flipped classes and team-based learning projects.

The slides and the handouts used during the classes will be available on the POLITO Didattica web portal. The following books provide a useful reference for the topics discussed during the course. Classical optical communication systems, networks, and protocols: - Springer Handbook of Optical Networks, Springer, 2020 - J.F. Kurose, K.W. Ross: Computer Networking: A Top-Down Approach Featuring the Internet Quantum optical communication networks: - “Quantum Communication, Quantum Networks, and Quantum Sensing” by Ivan B. Djordjevic - "Quantum Networking" by Rodney Van Meter

Slides; Dispense; Libro di testo; Esercizi risolti; Esercitazioni di laboratorio; Esercitazioni di laboratorio risolte; Video lezioni dell’anno corrente; Materiale multimediale ; Strumenti di simulazione; Strumenti di collaborazione tra studenti;

Modalità di esame: Prova scritta (in aula); Prova orale facoltativa; Elaborato grafico prodotto in gruppo; Elaborato progettuale individuale; Elaborato progettuale in gruppo;

Exam: Written test; Optional oral exam; Group graphic design project; Individual project; Group project;

... Written test; Group research and presentation; Group project; Optional oral exam. The final evaluation is based on four parts. The first part is based on a group presentation. During the course, the teacher will briefly introduce a few advanced topics currently under investigation in the research community. The students will form groups of three to four people and will be assigned to prepare a 30-min presentation on one of the selected topics. The overall quality of the presentation will be evaluated on a scale from 1 to 5 points. The second part of the exam is based on a simulation project that builds upon the labs performed during the course. This part will be scored on a scale from 1 to 10 points. The project will be assigned in the second-last week of the course and must be completed within a week of the end of the course. The third part of the exam is based on a written test with exercises as well as open and multiple-choice questions. The written test will last up to 1.5 hours, and it will be scored on a scale up to 15 points. The evaluation of this part is based on the completeness of the answers, but also on the ability of the students to convey the necessary concepts in a concise way. This written exam is a “closed-book exam”. Students that wish to improve their overall grade can ask for an optional oral exam (which can give +- 5 points). The final exam grade will be the sum of the written test, presentation, and optional oral exam scores.

Gli studenti e le studentesse con disabilità o con Disturbi Specifici di Apprendimento (DSA), oltre alla segnalazione tramite procedura informatizzata, sono invitati a comunicare anche direttamente al/la docente titolare dell'insegnamento, con un preavviso non inferiore ad una settimana dall'avvio della sessione d'esame, gli strumenti compensativi concordati con l'Unità Special Needs, al fine di permettere al/la docente la declinazione più idonea in riferimento alla specifica tipologia di esame.