Multimode fiber based high-dimensional light analyzer

Abstract: The wavelength and state of polarization (SOP) are fundamental properties of an optical field which are essential for applications in optical communications, imaging and other fields. However, it is challenging for existing spectrometers and polarimeters to measure these parameters simultaneously, resulting in reduced spatial and temporal efficiency. To overcome this limitation, we propose and demonstrate a compact multimode fiber (MMF)-based high-dimensional light analyzer capable of simultaneously performing high-precision measurements of both wavelength and SOP. Core-offset launching is introduced in the MMF to reshuffle the mode coupling. A neural network named WP-Net has been designed dedicated to wavelength and SOP synchronization measurements. Physics-informed loss function based on optical prior knowledge is used to optimize the learning process. These advancements have enhanced the sensitivity, achieving a wavelength resolution of 0.045 pm and an SOP resolution of 0.0088.