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arXiv · 2609.27709

A native signed incoherent photonic matrix core on thin-film lithium niobate supporting in situ backpropagation

Yuan Ren·Yong Zheng·Ruixue Liu·Min Wang·Ya Cheng
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Abstract

Artificial intelligence workloads increasingly demand computing architectures combining high throughput, energy efficiency, and physical scalability. Here we present a signed incoherent optical matrix multiplier on thin-film lithium niobate that natively supports signed inputs and weights. We demonstrate closed-loop in situ backpropagation on a 16 X 16 photonic core, including forward computation, nonlinear operations, error propagation, and gradient computation. Measured physical outputs directly participate in optimization, thereby incorporating actual device responses and nonidealities into training. The core achieves 8-bit multiplication and 10-bit accumulation precision across 256 channels, maintains 10-bit accuracy in tiled 256 X 256 matrix computation, and further executes Transformer linear operations in a BERT-mini workload. This work presents a fundamental, scalable building block that addresses key limitations in practical optical computing, thereby opening avenues for large-scale, high-efficiency photonic neuromorphic systems.

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Yuan Ren, Yong Zheng, Ruixue Liu, Min Wang, Ya Cheng. 2026-09-23. A native signed incoherent photonic matrix core on thin-film lithium niobate supporting in situ backpropagation. https://arxiv.org/abs/2609.27709

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