End-to-End Optical Semantic Communication over a Nonlinear WDM Fiber Link
Organizations: Department of Electronics and Telecommunications, Politecnico di Torino, Turin, Italy
Abstract
Emerging optical-network applications increasingly use received data for inference and control rather than exact source reproduction, creating an opportunity to trade bit-level fidelity for greater transmission reach and efficiency. We propose an end-to-end optical semantic communication system for joint image classification and reconstruction over a nonlinear wavelength-division multiplexed (WDM) fiber channel. The system maps each image directly into a fixed-length sequence of channel symbols that preserves task-relevant information, without explicit source compression or channel coding. Experiments on the MNIST dataset cover launch powers from -9 to +3 dBm, fiber lengths up to 800 km, and 16-, 64-, and 256-Quadrature Amplitude Modulation (QAM) formats. At 0 dBm, classification accuracy remains between 98.92% and 99.31% across all tested link lengths and modulation orders, while requiring fewer transmitted symbols than a Low-Density Parity-Check (LDPC)-coded JPEG baseline at every tested modulation order. These results show that semantic communication can simultaneously extend optical reach and reduce transmission resources by conveying only task-relevant information.
Figures & tables
| Symbol | Quantity | Value |
|---|---|---|
| Symbol rate | 32 GBaud | |
| Samples per symbol | 16 | |
| RRC filter length | 1024 taps | |
| RRC roll-off factor | 0.01 | |
| Number of WDM channels | 11 | |
| WDM channel spacing | 37.5 GHz |
| Scheme | Symbols/image | Transmission time [ns] |
|---|---|---|
| Semantic system | 128/128/128 | 4.0/4.0/4.0 |
| Uncoded JPEG | 233/155/117 | 7.3/4.9/3.7 |
| LDPC-coded JPEG | 466/311/233 | 14.6/9.7/7.3 |