100-Gbit/s 100-km Physical-Layer Secure Fiber-Optic Communication Using Wideband Chaotic Semiconductor Lasers

Optical chaos communications have been proposed for secure data transmission with the potential of high bit rate and compatibility with existing fiber-optic systems. Semiconductor lasers are excellent candidate of chaotic transceivers thanks to their easy-to-integrate structures and high chaos complexity, but still encounter a key challenge that the transmission rate is lagged far behind the fiber-optic communication. Here, we experimentally demonstrate 100-Gbit/s optical chaos communication towards secure metropolitan transmission. State-of-the-art broadband chaos synchronization with a carrier bandwidth of 31.7 GHz is obtained by employing discrete-mode semiconductor lasers under the three-laser scheme, where two lasers are commonly driven by a third chaotic laser. The three-laser scheme also breaks the frequency limitation of laser relaxation oscillation on chaos cancellation decryption. Experiments achieve chaos-masking communication of 25-GBaud 16-QAM message over 100 km transmission with a bit error ratio of 1.6×10⁻², under assistance of digital signal processing. This work provides a solution to high-speed laser-chaos communication and facilitates the practical application of optical chaos communication in metropolitan area networks.