State of the art in optical switching technologies for all optical networks

In this thesis, all optical networks eliminate electro-optical conversions, enabling unprecedented data speeds exceeding 100 Tbps. The thesis presents a systematic review of optical switching technologies from 2014 to 2024, with emphasis on advancements from 2019 to 2024. Findings show that reported switching times for silicon photonic devices span picoseconds to milliseconds, depending on the mechanism; picosecond-scale for depletion-mode modulators and microsecond to millisecond for thermo-optic phase shifters. In this work, we assume sub-nanosecond switching only for depletion mode devices, while MEMS-based solutions scale to 512×512 ports. Hybrid graphene-silicon modulators demonstrate 40 Gbps operation at 5 fJ/bit. Critical limitations include thermal crosstalk ≈ of approximately −35 dB in 3D integrated circuits and gaps in control plane standardization. On the other hand, quantum dot routers demonstrate 99.7% single-photon routing fidelity [1]. The study concludes with a roadmap for neuromorphic photonics and 2D material based switches.