The quantum properties of light are no longer just a curiosity, they’re becoming a tool for technologies that could reshape communication and computing. Projects in entangled communication, networked quantum computing, and precision sensing now allow researchers to shape technologies that could truly transform information science. Yet the field continues to struggle with a familiar problem: how to make entangled photon pairs efficiently at telecom wavelengths [1]. 

Silicon nitride (SiN) waveguides have emerged as a reliable platform in quantum photonics. They are compatible with standard semiconductor manufacturing, exhibit broad optical transparency, and, unlike silicon, avoid issues with two-photon absorption. However, the material’s intrinsic nonlinearity is relatively weak, which limits both the efficiency and tunability of photon-pair generation [2]. This limitation has nudged researchers to look toward materials that can do what SiN cannot. 

Two-dimensional semiconductors like monolayer WSe₂ offer a promising alternative. They display remarkably strong excitonic nonlinearities orders of magnitude larger than typical dielectric materials which, according to theoretical estimates, could enhance spontaneous four-wave mixing (SFWM) and improve the efficiency of entangled-photon generation [3]. These atomically thin layers are highly delicate any misplaced flake, residual contamination, or uneven interface can seriously affect performance [4]. So far, most studies have only explored single-photon emission or simple waveguide coupling, leaving a complete hybrid system with both enhanced nonlinearity and active control unexplored. 

This PhD project focuses on exploring how a carefully designed SiN- WSe₂ platform can improve nonlinear light generation while staying compatible with larger photonic circuits. The aim is not to reinvent quantum photonics, but to demonstrate that design choices such as dispersion engineering, material encapsulation, and electrical tuning can address a key challenge in the field. 

PhD Timeline and Phases: 

Year 1 – Simulation and Design: Focus on waveguide geometry and dispersion near 1550 nm using Lumerical and COMSOL, tweaking layer thickness, width, and cladding to optimize mode confinement. Some trade-offs between enhancement and loss are expected. Attend seminars, workshops, and possibly an international conference to present preliminary results. Deliverables: optimized designs and simulation reports with initial assessments. 

Year 2 – Fabrication: Move into the lab to deposit, pattern, and etch Si₃N₄ waveguides. Hands-on cleanroom work and cross-lab collaboration will be key. Deliverables: hybrid SiN–WSe₂ devices, successful monolayer transfer, and process documentation. 

Year 3 – Characterization: Test devices under pulsed laser excitation to measure insertion loss, photon-pair generation, CAR, and heralding efficiency. Expect surprises that may require revisiting simulations. Deliverables: performance metrics, Joint Spectral Intensity JSI maps, and updated guidance. Publications in peer-reviewed journals and conference proceedings. 

Year 4 – Integration: Assemble devices into an on-chip system and test coupling, stability, and feasibility for quantum photonics. Present at conferences and prepare manuscripts. Deliverables: fully integrated entangled-photon source, system-level results, and final thesis chapters, with potential collaborative publications.