We have observed various polarization domains and a giant self-mode-locked pulse in a 130 m long erbium-doped fiber laser without any mode-locking devices. By adjusting the intra-cavity

We have observed various polarization domains and a giant self-mode-locked pulse in a 130 m long erbium-doped fiber laser without any mode-locking devices. By adjusting the intra-cavity polarization controller, we investigated the evolution process of the polarization domain with the cavity birefringence varying. When the birefringence was close to zero, the polarization domains split into multi-domains, and finally a giant self-mode-locked pulse formed for the first time. We analyzed that the generation of the self-mode-locked pulse was related to the multiple sub-domains ascribed to the strong coherent cross coupling between the orthogonal polarization light components in the long fiber cavity.show less

A diode-pumped continuous-wave Tm:YVO₄ laser operating on the ³H₄ → ³H₅

A diode-pumped continuous-wave Tm:YVO₄ laser operating on the ³H₄ → ³H₅ and ³F₄ → ³H₆ transitions was demonstrated for the first time, to the best of our knowledge. An a-cut Tm:YVO₄ crystal with 1.5 at. % Tm³⁺ ion concentration was used to characterize the laser behavior. A common commercial laser diode with a central wavelength of 790 nm and a bandwidth of 3.2 nm was utilized as a pump source. With an output coupler for the ³H₄ → ³H₅ and ³F4 → ³H₆ transitions, simultaneous three-wavelength laser operation was achieved. The laser emissions at 2292 and 2363 nm in π-polarization and at 2108 nm in σ-polarization were realized. With an incident pump power of 22 W, the total output power of 1.17 W at 2292 nm, 2363 nm and 2108 nm was obtained. The output power at 2292 and 2363 nm was measured to be 750 mW, and the output power at 2108 nm was measured to be 420 mW. show less

Self-healing in optics generally refers to the ability to self-reconstruct and restore the original state after encountering obstacles in the propagation of the light field. In this res

Self-healing in optics generally refers to the ability to self-reconstruct and restore the original state after encountering obstacles in the propagation of the light field. In this research, we observe the processes of the wave-fields from perfect to defect in front of the focal plane of the 4f system, finally returning to intact situation after the plane. According to simulations and experimental results, there is a minimum self-healing distance for the moiré lattice field that positively associates with the radius of the defect (obstacle) in the non-diffracting transmission range. Furthermore, it is observed that the defect self-healing is a process of “repairing the center and then repairing the edges”. These findings can be applied in areas such as optical imaging, capture, and information processing.show less

We propose an alternative approach to compensation of intermodal interactions in few-mode optical fibers by means of digital back-propagation. Instead of solving the inverse generalized

We propose an alternative approach to compensation of intermodal interactions in few-mode optical fibers by means of digital back-propagation. Instead of solving the inverse generalized multimode nonlinear Schrödinger equation, we accomplish backpropagation of the multimode signals with help of their near-field intensity distributions captured by a camera. We demonstrate that this task can successfully be handled by a deep neural network and provide a proof of concept by training an autoencoder for backpropagation of six LP modes of a step index fiber.show less