Efficient dispersion modeling in optical multimode fiber

Optoelectronic oscillator using visible LEDs and plastic optical fibers

This paper describes an optoelectronic oscillator (OEO) capable of accepting CW light as input and providing radio-frequency (RF) carriers as output. To the best of our knowledge, we are the first to describe an easy-to-assemble and low-cost OEO that uses visible LED sources with a standard 1 mm diameter plastic optical fiber as part of the oscillation ring. The gain is solely provided by a transimpedance pre-amplifier integrated with a photodetector. Self-oscillations occurred. Fundamental frequencies in the 7.7-26.5 MHz range were generated, since the length of the fiber and the bias current feeding the LED are both correctly tuned. A comprehensive approach is used to explain the operation of the OEO. The proposed OEO may be didactically useful for use in research or teaching laboratories by untrained people.

Wide-field color imaging through multimode fiber with single wavelength illumination: plug-and-play approach

Multimode fiber (MMF) is extensively studied for its ability to transmit light modes in parallel, potentially minimizing optical fiber size in imaging. However, current research predominantly focuses on grayscale imaging, with limited attention to color studies. Existing colorization methods often involve costly white light lasers or multiple light sources, increasing optical system expenses and space. To achieve wide-field color images with typical monochromatic illumination MMF imaging system, we proposed a data-driven "colorization" approach and a neural network called SpeckleColorNet, merging U-Net and conditional GAN (cGAN) architectures, trained by a combined loss function. This approach, demonstrated on a 2-meter MMF system with single-wavelength illumination and the Peripheral Blood Cell (PBC) dataset, outperforms grayscale imaging and alternative colorization methods in readability, definition, detail, and accuracy. Our method aims to integrate MMF into clinical medicine and industrial monitoring, offering cost-effective high-fidelity color imaging. It serves as a plug-and-play replacement for conventional grayscale algorithms in MMF systems, eliminating the need for additional hardware.