Robust Directional Couplers for State Manipulation in Silicon Photonic-Integrated Circuits

Photonic integrated circuits play a central role in current and future applications such as communications, sensing, ranging, information processing. quantum computing will also likely require an optics architecture for improved stability, scalability, performance. Fault-tolerant mandates very accurate robust gates. In this work, we demonstrate high-fidelity directional couplers single-qubit gates photonic waveguides, utilizing novel scheme of detuning-modulated composite segments. Specific designs reduced sensitivity to wavelength variations real-world geometrical fabrication errors waveguides width depth are presented. Enhanced tolerance is demonstrated experimentally. The concept shows great promise scaling high fidelity part architectures.