Research on long-short parallel optical buffer system based on multi-core fiber

As optical communication networks evolve toward high capacity, low latency, and high integration, traditional optical buffering systems based on single-core fibers exhibit inherent limitations in terms of delay flexibility, tuning range, and system integration. Multi-core fiber is a transmission medium that integrates multiple independent cores within a single fiber. However, in the field of communications, it merely serves as a carrier for optical signal transmission, and its functional development has been limited. This paper proposes and demonstrates a long-short parallel optical buffering system based on multi-core fiber. Our method achieves the integrated application of communication and buffering in multi-core fiber, breaking through the functional limitations of a single device. By exploiting the spatial dimension multiplexing capability of multi-core fiber, two independent buffering paths—short buffer and long buffer—are constructed in parallel within the same fiber. The short buffer structure adopts a single-fiber-core circulating approach to achieve microsecond-precision fast delay tuning. The long buffer structure utilizes multiple fiber cores in series, combined with multi-loop circulation and distributed output control, to achieve a wide-range delay tuning from microseconds to sub-milliseconds. Simulation analysis is conducted on the effects of bending radius and core pitch on the delay difference in multi-core fiber. The results show that under experimental deployment conditions, the relative error caused by the delay difference is approximately 0.07 %. Experiments are conducted on a 1-km seven-core fiber platform. The measured delay of the short buffer is 5.0656 μs, while the long buffer achieves a delay range from 5.0656 μs to 30.0396 μs, with a delay step of 4.949 μs per additional core. The relative error is controlled within 1.4 %, and the measurement standard deviation is below 0.002 %. The proposed buffering system offers advantages such as high precision, wide range, and programmability, providing a new method and technical support for scenarios including all-optical switching and intelligent computing center interconnectivity.