Multi-Transverse-Mode Silicon Photonics for Quantum Computing

Photonics has been identified as a highly promising platform for optical classical and quantum computing. In the realm of classical computing, the inherent parallelism of optics, as opposed to the sequential operations of electronics, offers significant potential for achieving faster and more energy-efficient computational capabilities. Photonics also represents a highly advantageous option for the pursuit of integrated quantum computing, primarily due to the noise- and decoherence-free nature of single photons. Optical qubits can be effectively generated by encoding single photons in a given degree of freedom, such as polarization, path, or wavelength. Path encoded programmable quantum gates have already been realized in Silicon Photonics (SiPh), a technology platform offering several appealing features such as compatibility with complementary metal oxide semiconductor (CMOS) for high integration density. To achieve a large-scale photonic quantum system, encoding the information on other degrees of freedom, such as polarization and transverse mode, is essential. Here, we present an open access process design kit (PDK) for multitransverse-mode components compatible with standard 220 nm thick SiPh technology. Then, we discuss the use of the PDK components in developing multi-transverse-mode classic optical computing. We also investigate multiple transverse modes of light for encoding and manipulating information in quantum photonics.