Demonstration of the First Outdoor 2-μm-Band Real-Time Video Transmission Free-Space Optical Communication System Using a Self-Designed Single-Frequency Fiber Laser
Qi Qin, Ting Li, Fengping Yan, Ting Feng, Weiwei Sun, Wenguo Han, Dandan Yang, Xiangdong Wang, Chenhao Yu, Pengfei Wang, Dan Cheng, Ying Guo, XUEMEI DU, Yan Liu, Youchao Jiang, Kazuo Kumamoto, Hong Zhou, Yuping Suo
Abstract
In the present paper, we demonstrate the first outdoor free-space optical communication (FSOC) system with real-time video transmission in a 2-μm-band with a state-of-the-art data rate performance of 10 Gbit/s and a communication distance of ∼177 m. The measured wide-open eye diagram and zero bit-error-rate also validated the high communication quality. The FSOC system is constructed with all homemade components, including a single-frequency (SF) thulium-holmium co-doped fiber laser (THDFL), a modulation module, a demodulation module, three thulium-doped fiber amplifiers, an optical bandpass filter, two optical-antennas, and a display system. As the most important component, the SF THDFL, enabled by a uniform fiber Bragg grating and a passive fiber ring-compound cavity, is self-designed and fabricated by our group, presenting high lasing stability centered at 2048.98 nm, an optical signal-to-noise ratio of >81 dB, a relative intensity noise of <−128.18 dB/Hz at >0.5 MHz and a linewidth of 5.290 kHz under a measurement integration time of 0.001 s. Our work is an important step forward for practical outdoor FSOC in a 2-μm-band, proving useful for engineers and scientists when our SF THDFL is implemented as a low-cost, high-performance laser source for the FSOC system.