Photonic Directional Coupler for Beamsplitter and Optical MEMS Switch Applications

Abstract

Quantum computing promises revolutionary advancements in computational power by leveraging quantum mechanical phenomena such as superposition and entanglement. Diamond color centers have emerged as promising candidates for quantum information processing due to their long coherence times and scalability. Photonic integrated circuits (PICs), represent a mature technology that facilitates on-chip quantum operations in a compact and scalable manner. In quantum applications, PICs play a crucial role in routing and manipulating quantum information.

The transition to the "More than Moore era," following the plateauing of Moore's law, has highlighted the importance of MEMS (Micro-Electro-Mechanical Systems) technology for continued advancements in electronics. Integrating MEMS with PICs and quantum applications, due to its high performance and mass production capabilities, offers a promising avenue for large-scale device integration and multi-qubit systems.

Designing photonic devices for integration with diamond color-center qubits presents several challenges. Primarily, designing photonic devices for the visible spectrum involves challenges related to device feature sizes approaching the limits of fabrication resolution. Additional challenges include ensuring scalability in quantum computing and compatibility with complementary metal-oxide semiconductor (CMOS) electronics. This requires devices that operate with low power consumption, low actuation voltage, and minimal crosstalk, necessitating significant optimization of MEMS components. Furthermore, integrating MEMS devices demands careful consideration of the mechanical properties of the materials and the designed structures.

This project discusses the design, fabrication, and characterization of a photonic directional coupler for use in beamsplitter and optical MEMS switch configurations in the visible spectrum. The photonic beamsplitter is essential for the controlled manipulation of quantum states, crucial for executing quantum algorithms. The optical MEMS switch provides dynamic control over optical pathways, leveraging the advantages of photonics and MEMS technology. The goal of this project is to optimize the directional coupler design for footprint, and fabrication accuracy, and to propose a directional coupler-based optical MEMS switch design that features low actuation voltage and high extinction ratio. Additionally, this project aims to establish the process recipes for fabricating the designed directional couplers and MEMS components, with particular attention to the physical resolution of small feature sizes, and to evaluate the extent to which the designed performance is achieved. By addressing these topics, the project aims to contribute to the large-scale integration of diamond color center qubits for quantum computing applications.