Spectral Shaping Enabled Mode Control and Information Transmission Through a Multimode Optical Fiber

Mode control in multimode optical fibers (MMFs) is an emerging technology for information transmission, which has been studied extensively for ultra-thin fiber endoscopes and optical communication. Here, we propose the concept of spectral shaping to modulate light spatially through a MMF. Experimental results show that the proposed method can realize arbitrary spatial mode control by shaping the spectra of the input light. Benefitting from the wavelength-dependent mode control, two scenarios of spatial-sensitive information transmission are demonstrated, i.e., encrypted information transmission and dual-channel transmission. This work expands ways of mode modulation (spatial control) in MMFs to the spectral domain, providing a new perspective for light control with high feasibility, simple operation, concise scheme, all-fiber structure, and abundant degrees of modal freedom.