Simulating integrated photonic gates using FDTD

Abstract

Quantum technologies, such as quantum communication, quantum sensing, quantum imaging and quantum computation, need a platform which is flexible, miniaturisable and works at room temperature. Integrated photonics is a promising and fast-developing platform. This requires to develop the right tools to design and fabricate arbitrary photonic quantum devices. Here we present an algorithm which, starting from a n-mode transformation U, designs a photonic device that approximates U. Using this method we design integrated photonic devices which implement quantum gates with high fidelity. Apart from quantum computation, future applications include the design of photonic subroutines and embedded quantum devices. These custom-designed photonic chips will be able to implement a given algorithm as a single-block circuit and will be small, robust and fast compared to a fully-programmable processor.