Recently, the team led by Prof. Zhan Qiwen published a new research achievement titled “Generation and applications of spectral-spatially correlated principal mode in multimode fibers” in Optica, a flagship journal of the Optical Society of America. Ph.D student Gao Han was the first author; Prof. Zhan Qiwen and Prof. Hu Haifeng were the corresponding authors. USST was the first unit.
Multimode fiber (MMFs) are intricate yet versatile systems, occupying pivotal roles across diverse applications, spanning from optical transmission, imaging, sensing, to high-power lasers. In all these diverse applications, the ability of MMF to support a multitude of transverse optical modes is a double-edged sword, representing both a critical feature and a significant challenge. The inevitable random mixing of modes with different propagation constants, along with modal dispersion, results in substantial frequency-dependent distortion of the light field after propagating through MMF. In this study, the research team presents for the first time the utilization of a special light state, referred to as the spectral-spatially correlated principal modes, which can be conveniently abbreviated as S2 principal modes, to simultaneously customize the output light field in MMF in both spectral and spatial dimensions. Compared to the traditional frequency-only principal modes, the S2 principal mode not only exhibits similar spectral characteristics but also expands the concept and application scope of principal modes further, enabling simultaneous customization of multiple parameters.
The research team demonstrates the application of S2 principal modes for secure optical information transmission through multi-mode optical fibers. This S2 principal mode offers a secure way to transmit information through physical layer encryption, without the necessity of pre-established secure channels and keys. The S2 principal mode proposed in this study exhibits significant potential for applications in imaging, sensing, and communication, and its inherent universality enables seamless extension to other multimode waveguide or linear propagation systems.
The research is granted by National Natural Science Foundation of China and Natural Science Foundation of China.
