A software platform for quantum computing is required to run a complex algorithm on a real quantum device through automatically converting a quantum circuit level algorithm to a control sequence of target device. Moreover, the software platform must be tailored for the target quantum system by exploiting the properties of qubits and gates. In this work, we show how to implement a software platform for a photonic integrated circuit (PIC) platform with path-encoded photon qubits and quantum gates realized by means of interference in a mesh of tuneable Mach-Zehnder interferometers (MZIs). For universal and programmable quantum computing, the software platform consists of three standard modules: decomposer, mapper, and controller. To verify the software we runs example circuit through software and hardware integration platform and confirm each module generates correct output. Also the validation is done by comparing two results for conventionally used manual way and the software supported automatic way. These two points ensure that the implemented software works correctly when applied to the PIC.
A software platform for quantum computing is required to run a complex algorithm on a real quantum device through automatically converting a quantum circuit level algorithm to a control sequence of target device. Moreover, the software platform must be tailored for the target quantum system by exploiting the properties of qubits and gates. In this work, we show how to implement a software platform for a photonic integrated circuit (PIC) platform with path-encoded photon qubits and quantum gates realized by means of interference in a mesh of tuneable Mach-Zehnder interferometers (MZIs). For universal and programmable quantum computing, the software platform consists of three standard modules: decomposer, mapper, and controller. To verify the software we runs example circuit through software and hardware integration platform and confirm each module generates correct output. Also the validation is done by comparing two results for conventionally used manual way and the software supported automatic way. These two points ensure that the implemented software works correctly when applied to the PIC.
Universal multiport interferometers based on Mach–Zehnder meshes are becoming a core building block for photonic neural-network accelerators and photonic quantum processors. This thesis presents the design, calibration, and control of such a programmable photonic integrated circuit (PIC). A fully automated software and hardware platform is developed to characterize and control the tunable elements of the PIC, enabling robust implementation of arbitrary linear optical transformations as well as target unitary operations. Using the calibrated device model, the control framework programs the PIC to realize specific unitaries and evaluates their performance through fidelity metrics computed from measured transfer matrices. By covering the complete stack from chip design to automated calibration and high-level unitary programming, this work establishes a scalable framework for design and operation of programmable photonic processors.
Interest in quantum computing is rapidly growing in the scientific community as such technology could be the key to enable intensive use of machine learning and big data algorithms. Quantum computers can be conceived from basic photonic elements, such as Mach-Zehnder interferometers (MZI), but they still need control mechanisms and sensing elements from traditional VLSI technology. In this study, we present an ongoing study on a potential architecture for these basic photonic circuits. We realized two Photonic Integrated Circuit (PIC) test structures embedding metallic thermistors as phase shifters and silicon photodiodes as output detectors. We present a complete characterization of the phase shifter elements for an effective on-chip PIC interaction. To induce a consistent phase shift still retaining coherence of light, we act on the phase-shifters by means of a closed-loop control. By controlling through Pulse-Width Modulation the phase shifters, we drive the path of photons accurately in the PIC, demonstrating the effectiveness of the proposed configuration for the management of a photonic chip.
We present a photonic integrated circuit architecture for a quantum programmable gate array (QPGA) capable of preparing arbitrary quantum states and operators. The architecture consists of a lattice of phase-modulated Mach-Zehnder interferometers, which perform rotations on path-encoded photonic qubits, and embedded quantum emitters, which use a two-photon scattering process to implement a deterministic controlled-${\ensuremath{\sigma}}_{z}$ operation between adjacent qubits. By appropriately setting phase shifts within the lattice, the device can be programmed to implement any quantum circuit without hardware modifications. We provide algorithms for exactly preparing arbitrary quantum states and operators on the device, and we show that gradient-based optimization can train a simulated QPGA to automatically implement highly compact approximations to important quantum circuits with near-unity fidelity.
Optical quantum computers represent qubits as photons created by laser and implement arbitrary quantum operations through Mach-Zehnder interferometers (MZIs) which is called linear optical quantum computing (LOQC). Since the number of qubits and quantum system is getting bigger, we need a scalable and universal quantum computing platform based on LOQC. In this work, we propose a software framework which can support a universal programming with flexibility of LOQC hardware configuration. The framework consists of four parts such as decomposer, mapper, controller, and user-interface controller. As an example, we show a use case of this framework for Bell state generation on Recket al.’s MZI network.
Linear optical quantum computing (LOQC) offers a quantum computation paradigm based on well-established and robust technology and flexible environmental conditions following DiVincenzo's criteria. Within this framework, integrated photonics can be utilized to achieve gate-based quantum computing, defining qubits by path-encoding, quantum gates through the use of Mach-Zehnder interferometers (MZIs), and measurements through single-photon detectors. In particular, universal two-qubit gates can be achieved by suitable structures of MZIs together with post-selection or heralding. The most resource-efficient choice is given by the post-selected Controlled-Z (CZ) gate. However, this implementation is characterized by a design which has a non-regular structure and cannot be cascaded. This limits the implementation of large-scale LOQC. Starting from these issues, we suggest an approach to move toward a universal and scalable LOQC on the integrated photonic platform. First of all, choosing the post-selected CZ as a universal two-qubit gate, we extend the path-encoded dual-rail qubit to a triplet of waveguides, composed of an auxiliary waveguide and the pair of waveguides corresponding to the qubit basis states. Additionally, we introduce a swap photonic network that maps the regularly-labeled structure of the new path-encoded qubits to the structure needed for the post-selected CZ. We also discuss the optical swap gate that allows the connection of non-nearest neighbor path-encoded qubits. In this way, we can deterministically exchange the locations of the qubits and execute controlled quantum gates between any path-encoded qubits. Next, by truncating the auxiliary waveguides after any post-selected CZ, we find that it is possible to cascade this optical gate when it acts on different pairs that share only one qubit. Finally, we show the Bell state and the Greenberger-Horne-Zeilinger (GHZ) state generation circuits implementing the regular structure, the cascading procedure of post-selected CZ and the optical swap.
Programmable photonic integrated circuits are emerging as increasingly large and versatile interferometric processors operating at room temperature. However, their native operations are linear, while many computational tasks require nonlinear input-output transformations that typically rely on nonlinear optical materials or resonant devices. Here, we establish a direct mapping between quantum signal processing (QSP) and the native two-mode operations of programmable interferometric photonic integrated circuits, showing that the SU(2) structure required by QSP can be realized through programmable phase control and mode mixing. We experimentally demonstrate this correspondence using dual-rail single-photon encoding on a 24-mode programmable photonic integrated circuit, realizing QSP sequences up to depth L=11 and synthesizing STEP, ReLU and SELU functions through programmable phase control. The optical transformation remains linear, while repeated encoding of the input variable and coherent interference produce a nonlinear dependence of the output probabilities on the encoded variable. Across all accessible circuit depths, the measured responses follow the programmed QSP transformations, with hardware-induced mean squared errors between 10−3 and 10−2, all remaining below the intrinsic finite-depth approximation error. These results establish an algorithm-to-hardware mapping of QSP on programmable photonic processors. They also demonstrate an algorithmic route to programmable nonlinear functions of encoded variables on linear photonic hardware.