2025-06-06 東京大学
光導波路多重型シリコン光行列演算回路
＜関連情報＞
- https://www.t.u-tokyo.ac.jp/press/pr2025-06-06-001
- https://www.t.u-tokyo.ac.jp/hubfs/press-release/2025/0606/001/text.pdf
- https://opg.optica.org/optica/fulltext.cfm?uri=optica-12-6-812&id=572538
マルチポート光検出器を用いた導波路多重フォトニック行列・ベクトル乗算プロセッサ Waveguide-multiplexed photonic matrix–vector multiplication processor using multiport photodetectors
Rui Tang, Makoto Okano, Chao Zhang, Kasidit Toprasertpong, Shinichi Takagi, and Mitsuru Takenaka
Optica Published: 4 June 2025
DOI:https://doi.org/10.1364/OPTICA.552023
Abstract
The slowing down of Moore’s law has driven the development of application-specific processors for deep learning. Analog photonic processors offer a promising solution for accelerating matrix–vector multiplications (MVMs) in deep learning by leveraging parallel computations in the optical domain. Intensity-based photonic MVM processors, which do not utilize the phase information of light, are appealing due to their simplified operations. However, existing intensity-based schemes for such processors often employ wavelength multiplexing or mode multiplexing, both of which have limited scalability due to high insertion loss or wavelength crosstalk. In this work, we present a scalable intensity-based photonic MVM processor based on the concept of waveguide multiplexing. This scheme employs multiport photodetectors (PDs) to sum the intensities of multiple optical signals, eliminating the need for multiple wavelengths or modes. A 16-port Ge PD with a 3 dB bandwidth of 11.8 GHz at a bias voltage of −3V is demonstrated, and it can be further scaled up to handle 250 ports while maintaining a 6.1 GHz operation bandwidth. A 4×4 circuit fabricated on a Si-on-insulator platform is used to perform MVMs in a three-layer neural network designed for classifying Iris flowers, achieving a classification accuracy of 93.3%. Furthermore, the performance of large-scale circuits in a convolutional neural network for Fashion-MNIST is simulated, resulting in a classification accuracy of 90.53%. This work provides a simplified and scalable approach to photonic MVM, laying a foundation for large-scale and multi-dimensional photonic matrix–matrix multiplication in optical neural networks.
