Equalization based on artificial neural networks (NN) has proved to be an effective way for nonlinearity mitigation in various kinds of optical communication systems. In this Letter, we propose a novel methodology of dual-path neural network (DP-NN)-based equalization. By combining a linear equalizer with an input-pruned NN equalizer, DP-NN can effectively reduce the computation cost compared to a conventional NN equalizer. We confirm its feasibility through 4-ary pulse amplitude modulation (PAM4) transmission at a gross(net) bitrate of 160 Gb/s (133.3 Gb/s), based on a GeSi electro-absorption modulator operating at C-band. After a 2 km transmission, the bit error rate is below the 20% hard-decision forward-error-correction threshold of 1.5×10 with the DP-NN equalization, which outperforms the Volterra equalization and is comparable to conventional NN-based equalization.
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http://dx.doi.org/10.1364/OL.401242 | DOI Listing |
Light Sci Appl
January 2025
Wuhan National Laboratory for Optoelectronics, Next Generation Internet Access National Engineering Laboratory, and Hubei Optics Valley Laboratory, School of Optical and Electronic Information, Huazhong University of Science and Technology, Wuhan, 430074, China.
We propose and validate a novel optical semantic transmission scheme using multimode fiber (MMF). By leveraging the frequency sensitivity of intermodal dispersion in MMFs, we achieve high-dimensional semantic encoding and decoding in the frequency domain. Our system maps symbols to 128 distinct frequencies spaced at 600 kHz intervals, demonstrating a seven-fold increase in capacity compared to conventional communication encoding.
View Article and Find Full Text PDFIn this Letter, we propose a high-performance optimized detection scheme based on a neural network (NN) in a receiver digital signal processing (DSP) for bandwidth-limited intensity modulation and direct detection (IM/DD) transmission systems. The NN-based optimized detection scheme consists of two components, an NN-based lookup table (NN-LUT) and an NN-based log-maximum estimation with a fixed number of surviving state (NN-MAP) decoder. The NN-LUT provides more accurate and sufficient information (PI) to the decoder than the conventional filter-form PI without increasing computational complexity.
View Article and Find Full Text PDFSensors (Basel)
December 2024
State Key Laboratory of Integrated Chips and Systems, Fudan University, Shanghai 200433, China.
In this work, we implemented a short-reach real-time optical communication system using MLP for pre-distortion. Lookup table (LUT) algorithms are commonly employed for pre-distortion in intensity modulation and direct detection (IM/DD) systems. However, storage limitations typically restrict the LUT pattern length to 9, limiting its effectiveness in compensating for nonlinear effects.
View Article and Find Full Text PDFPolymers (Basel)
November 2024
State Key Laboratory of Advanced Optical Communication Systems and Networks, Shanghai Jiao Tong University, Shanghai 200240, China.
We design and fabricate meter-scale long connectorized paper-like flexible multimode polymer waveguide film with a large bandwidth-length product (BLP) for board-level optical interconnects application. The measured BLP of the multimode waveguide is greater than 57.3 GHz·m at a wavelength of 850 nm under the strictest overfilled launch condition with a maximum length of 2.
View Article and Find Full Text PDFO-band intensity modulation and direct detection (IM/DD) transmission offers a promising solution for high-speed data center interconnects (DCIs). Additionally, the introduction of bismuth-doped fiber amplifiers (BDFAs) results in less nonlinear impact and a higher link budget compared with semiconductor optical amplifiers (SOAs). However, with these key issues resolved, the system bandwidth limitation emerges as the next critical bottleneck for high-speed O-band DCI transmission that limits overall performance.
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