The growing demand for scalable and fault-tolerant platforms for classical and quantum information processing drives the search for integrated photonic systems tolerant of coherence constraints and architectural limitations. This thesis investigates the photonic mesh lattice (PML), a dynamically modulated, fiber-based architecture employing time-division multiplexing, as a robust and reconfigurable testbed for classical and quantum wave dynamics. The research addresses bottlenecks in existing technologies, such as reliance on bulky interferometric setups and lack of scalable architectures, by demonstrating a compact, fiber-loop-based system with dynamic coupling control. In the classical regime, the PML enables stable propagation of coherent light pulses over thousands of kilometers with minimal signal degradation. Losses are mitigated using optical amplifiers, while amplitude and phase modulation provide tunable control over signal dynamics. Results show the system supports long-distance propagation with high signal integrity, establishing the PML as a candidate for classical photonic networks and long-haul communication. In the quantum domain, the PML facilitates generation, manipulation, and interference of time-bin entangled photon pairs across multiple temporal dimensions. Dynamically reconfigurable coupling allows loophole-free quantum interference measurements and scalable quantum walks, enabling protocols such as quantum phase estimation, boson sampling, and high-dimensional entanglement processing. The fiber-based structure, compatible with telecom components, ensures economic viability and experimental accessibility. Beyond demonstrated applications, the PML opens doors to novel regimes, including simulation of synthetic gauge fields and optical trapping dynamics. This work contributes to unified optical platforms by integrating dynamic control, high-dimensional scalability, and robust signal processing in a compact architecture.
The growing demand for scalable and fault-tolerant platforms for classical and quantum information processing drives the search for integrated photonic systems tolerant of coherence constraints and architectural limitations. This thesis investigates the photonic mesh lattice (PML), a dynamically modulated, fiber-based architecture employing time-division multiplexing, as a robust and reconfigurable testbed for classical and quantum wave dynamics. The research addresses bottlenecks in existing technologies, such as reliance on bulky interferometric setups and lack of scalable architectures, by demonstrating a compact, fiber-loop-based system with dynamic coupling control. In the classical regime, the PML enables stable propagation of coherent light pulses over thousands of kilometers with minimal signal degradation. Losses are mitigated using optical amplifiers, while amplitude and phase modulation provide tunable control over signal dynamics. Results show the system supports long-distance propagation with high signal integrity, establishing the PML as a candidate for classical photonic networks and long-haul communication. In the quantum domain, the PML facilitates generation, manipulation, and interference of time-bin entangled photon pairs across multiple temporal dimensions. Dynamically reconfigurable coupling allows loophole-free quantum interference measurements and scalable quantum walks, enabling protocols such as quantum phase estimation, boson sampling, and high-dimensional entanglement processing. The fiber-based structure, compatible with telecom components, ensures economic viability and experimental accessibility. Beyond demonstrated applications, the PML opens doors to novel regimes, including simulation of synthetic gauge fields and optical trapping dynamics. This work contributes to unified optical platforms by integrating dynamic control, high-dimensional scalability, and robust signal processing in a compact architecture.
Quantum photonic resources are critical for advanced applications such as quantum computation, communication, and information processing. Efficient generation and detection of quantum states, as well as reliable photon manipulation techniques, are essential for the development of practical quantum technologies. Integrated photonic platforms offer attractive solutions due to their stability, small device footprint, and improved power efficiencies. However, optical loss and environmental noise hinder their capability to transmit, measure, and detect quantum states with high accuracies. To tackle these limitations, we have developed robust solutions for quantum signal processing by leveraging infrastructures from telecommunications and integrated photonics. These approaches focus on the use of silicon-based photonic sources for entanglement generation in the time and frequency degrees of freedom, as well as chip- and fiber-based architectures for entanglement verification via quantum interference and tomography measurements. Our photonic schemes allow for high-dimensional entanglement processing, demonstrating their versatility in developing scalable and cost-efficient quantum signal processing platforms.
Quantum communication promises unconditional security by leveraging the fundamental laws of quantum physics, which make eavesdropping detectable through the disturbance it introduces in quantum states. A cornerstone of this technology is quantum key distribution (QKD), enabling the distribution of a shared secret key between distant users with information- theoretic security, rather than relying on assumptions about an eavesdropper’s computational power, as in classical cryptography. However, current QKD systems rely largely on bulk-optical solutions, which limits scalability, stability, and integration into existing telecommunication infrastructures. Photonic integrated circuits (PICs) offer a promising platform to overcome these challenges by providing compact, stable, and CMOS-compatible architectures. This PhD work investigates integrated photonic platforms for practical quantum communication at telecommunication wavelengths, with a focus on demonstrating QKD protocols across three different encoding schemes: time-bin, frequency-bin, and path. First, a time-bin QKD receiver using a borosilicate-glass integrated imbalanced Mach–Zehnder interferometer (iMZI) is developed and compared with a fiber-based receiver, showing enhanced phase stability and improved long-distance secure key rates. Next, frequency-bin entanglement-based QKD is implemented using silicon microring resonators, demonstrating high-visibility quantum interference and active phase-stabilization techniques. Finally, a chip-to-chip path-entangled QKD link is realized using silicon photonic spiral sources, representing a crucial step toward fully integrated quantum transceivers. Across these experiments, this PhD thesis establishes a unified experimental framework for integrated QKD and evaluates performance in terms of quantum bit error rate, secure key rate, and system stability under realistic operating conditions. Together, the results provide a proof-of-concept demonstration of scalable, high-performance quantum communication using PIC technology, advancing toward practical deployment in future quantum networks and laying foundations for multidimensional and fully integrated quantum communication nodes.
Quantum networking enables the distribution of quantum information across distant nodes, unlocking capabilities such as secure communication, distributed quantum computing, enhanced metrology, and tests of fundamental physics. Photons serve as the natural carriers of quantum information over long distances due to their low loss in optical fibers and robustness to environmental decoherence. However, the practical realization of quantum networks remains limited by the lack of photon sources that are simultaneously compatible with diverse quantum systems, stable over long timescales, and suitable for deployment in real-world fiber infrastructure. This dissertation addresses these challenges through the co-development of photon-pair sources and a field-deployed quantum networking testbed. We present two complementary chip-scale sources of correlated photon pairs tailored for distinct bottlenecks in quantum networking. The first is a hybrid visible–telecom photon-pair source designed to address a fundamental spectral mismatch between quantum nodes and communication channels. While most quantum memories and processors operate at visible to near- nfrared wavelengths, optical fibers exhibit minimal loss in the telecommunications band. By integrating periodically poled nonlinear waveguides with photonic integrated circuits, we demonstrate a platform capable of directly generating visible–telecom photon pairs, enabling efficient interfacing between heterogeneous quantum systems and existing fiber networks. The second source is a fully packaged, broadband telecom photon-pair source based on silicon waveguide spirals, designed for stable, long-duration operation. This stability enables extended measurements necessary to overcome channel losses and environmental drifts in deployed fiber networks. These sources are evaluated within RoQNET (Rochester Quantum Network), a ∼20 km fiber link between the Rochester Institute of Technology and the University of Rochester. Using this platform, we demonstrate the transmission and on-chip modulation of heralded telecom single photons, verify their nonclassical statistics, and characterize long-term channel behavior. Additionally, we explore programmable time-bin entanglement distribution using spectral waveshapers, providing a flexible approach to quantum communication. Together, this work establishes a co-designed source–network framework for scalable, heterogeneous quantum networking.
Programmable waveguide circuits are crucial building blocks for integrated spectrometric applications and quantum photonic information processing. Amongst the dielectric material platforms in integrated photonics, silicon nitride stands out with highly attractive properties such as a large bandgap energy and a moderately high index contrast. This allows low propagation losses in a wide spectral range while simultaneously allowing a dense packing of components. The aforementioned properties, together with the inherent phase stability and phase programmability achievable in silicon nitride, enable the creation of complex photonic circuits. In this thesis we describe and demonstrate densely integrated programmable photonic circuits based on silicon nitride waveguides for wavelength metrology and quantum information processing. We concentrate on reconfigurable photonic integrated circuits based on silicon nitride waveguides with low-loss propagation, to explore interference in the spectral and temporal domain for advanced applications. We investigated two types of integrated interferometric devices featuring low loss in combination with programmability for classical and quantum photonic processing. The first is simple tunable microring resonator circuits in combination with neural network data processing for the analysis of classical light in the spectral domain as wavelength meter. The second is a complex tunable network of waveguide interferometers for controlling quantum correlations (coincidences) between single photons. Exploiting the long-term interferometric stability, low propagation loss and tight optical confinement of integrated silicon nitride waveguides, we have shown complex reconfigurable optical circuits both for classical and quantum photonic processing. For future development of integrated programmable photonic processors, various challenges need to be addressed such as compact and low-power phase shifters, a further increase of the component density and lower the propagation losses.
Encoding quantum information into time-bin entangled photons offers a physics-rich framework for both fundamental and applied quantum science. Here, we present two frameworks enabling the generation and manipulation of time-bin entangled photonic qudits for both fundamental and applied quantum information processing. The first framework consists of a scalable synthetic temporal photonic lattice implemented on a coupled fiber-loop system that is employed to explore and dynamically control the evolution of the discrete-time quantum walk of time-bin entangled photon states. The other framework consists of a modular, fiber-pigtailed, integrated photonic platform enabling the generation and processing of time-bin entangled qudits that were used to demonstrate the first Bennett-Brassard-Mermin 1992 QKD protocol extended to qudits. We operate the entangled qudits at processing speeds typical of standard telecommunication systems at 10s of GBaud.
Silicon photonics is a dynamic research field of integrated optics. It allows to miniaturize numerous optical functionalities such as lasers, electro-optical modulators, routers, detectors, for telecom wavelengths, LIDAR, sensor, metrology or even spectroscopy, all while been able to propose large scale production high precision technologies. On another side, quantum optics suffers from difficulties to scale optical systems, requires extreme stability, perfect alignment, and many bulky optical elements, while solving these issues follows a natural path in integrated photonics. Development of integrated quantum photonics can thus open the door to cheap, powerful, and scalable systems for quantum cryptography, telecoms, and computation. In a significant way, quantum requirements are not the ones of classical circuits with respect to photonic components and circuits. The generation of quantum states indeed requires more than 100dB of pump laser rejection, while being able to manage ultra-low useful optical signals and get rid of on-chip optical noise. In this context, this thesis is dedicated to the study, dimension, realization, and characterization of silicon photonic components and circuits for quantum optics on a chip. The target goal is to generate entangled states in energy-time and manipulate them on chip. The qualification of the quantum properties is also explored to better understand the limitations of the silicon platform in the followed objectives. Another choice of this work is to stay in telecoms wavelength and aligned with the standard channels (ITU grid), to only use off-the-shelf components, all while been CMOS compatible and compliant with standard fabrication process, this to allow the possibility to produce on large scale.