Abstract
Information and communication technology has continuously driven the demand for higher data transmission rates. At the same time, frequency synchronization technology also needs to continually adapt to the high-precision frequency references required between equipment in high-speed optical communication systems. However, existing time and frequency transmission technologies, which rely on the hardware-timestamp functions specified in IEEE1588, cannot meet the accuracy requirements for Precision Time Protocol (PTP) devices in 5G + or future 6G communications. Multi-core fiber, with its characteristics such as multi-channel transmission, superior symmetry, high integration, and versatility, is poised to become the preferred choice for next-generation communication fibers. There is a need to investigate the co-transmission of RF references and data signals based on multi-core fiber to further expand the capacity of communication data transmission and provide precise RF references for 5G + and future 6G communications. This paper proposes and experimentally demonstrates a novel approach for RF clock references and data signals co-transmission over a seven-core fiber on the same wavelength. By inserting an RF standard tone into the data signal spectrum through spectral modulation, we achieve co-transmission of a 10-MHz RF standard and 224-Gb/s dual-polarization 16-QAM signals over 1 km and 10 km seven-core fiber links based on frequency-synchronous optical network (FSON) architecture. The RF and data signals are received and demultiplexed entirely in the optical domain using a radio frequency and data signal demultiplexing (RFDSD) module. The measured 10-MHz frequency stability over 1 km and 10 km seven-core fiber links is better than commercial rubidium atomic clocks and it demonstrates the potential for picosecond-level clock dissemination within short-reach optical interconnects scenario. This work shows good performance in coherent demultiplexing of 224-Gb/s DP-16QAM signals with all tributaries demultiplexed below the 7% FEC threshold at receiver optical power levels of -19 dBm and − 18.5 dBm for 1 km and 10 km seven-core fiber links, respectively. Our approach provides a promising solution and theoretical foundation for next-generation high-speed, high-capacity, picosecond-level physical delay short-reach coherent optical interconnect applications.