Browsing by Author "Tao, Houchun"

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  • ItemOpen Access
    Reservoir computing using multimode fiber and spatial light modulator for mode decomposition - 10m MMF
    (Technische Universität Dresden, 2026-10-02) Tao, Houchun
    Multimode fibers (MMFs) are attractive for many applications, such as endoscopic imaging and internet data trans mission. However, modal dispersion leads to crosstalk effects. Robust mode decomposition is therefore crucial—whether to harness the inherent mode mixing for physical layer security (PLS) or to correct it in spatial division multiplexing (SDM). While traditional holographic methods can untangle this crosstalk, they require a stable reference beam, which is impractical for longhaul transmission due to environmental sensitivity. Furthermore, although recent deep-learning approaches enable reference-less decomposition, they typically suffer from high computational latency and massive training costs for dynamic channels. To overcome these limitations simultaneously, we propose a reference free, low-latency method for mode decomposition and channel reconstruction that leverages the linear complex scattering of the MMF as a passive high-dimensional spatial feature map, whose nonlinearity is provided by square-law detection at the camera. Following a reduction of the sampling rate in the frequency domain to decrease feature dimensionality, a computationally efficient linear readout layer inverts the scattering process to reconstruct the transmitted complex fields. Although the final channel reconstruction still requires digital computation steps, this readout process is limited to a single, computationally efficient linear matrix multiplication. This reduces both latency and computational overhead compared to conventional electronic neural networks, which typically exhibit high energy consumption and high latency. The physical limitations and trade-offs of this framework when scaling to higher modal complexities are also discussed. We experimentally demonstrate high-precision, reference-less mode decomposition for multiplexed classical optical fields.