A Review of Tunable Orbital Angular Momentum Modes in Fiber: Principle and Generation

Abstract

Orbital angular momentum (OAM) beams, a new fundamental degree of freedom, have excited a great diversity of interest due to a variety of emerging applications. The scalability of OAM has always been a topic of discussion because it plays an important role in many applications, such as expanding to large capacity and adjusting the trapped particle rotation speed. Thus, the generation of arbitrary tunable OAM mode has been paid increasing attention. In this paper, the basic concepts of classical OAM modes are introduced firstly. Then, the tunable OAM modes are categorized into three types according to the orbital angular momentums and polarization states of mode carrying. In order to understand the OAM evolution of a mode intuitively, three kinds of Poincaré spheres (PSs) are introduced to represent the three kinds of tunable OAM modes. Numerous methods generating tunable OAM modes can be roughly divided into two types: spatial and fiber-based generation methods. The principles of fiber-based generation methods are interpreted by introducing two mode bases (linearly-polarized modes and vector modes) of the fiber. Finally, the strengths and weaknesses of each generation method are pointed out and the key challenges for tunable OAM modes are discussed.

A Few-Mode-Fiber Platform for Quantum Communication Applications

“…The following figure shows 3 different OAM structures: The creation, propagation and detection of qudits has been desired over the years, but the natural bounds of the degrees of freedom of individual quantum systems have been a difficult challenge . Since (in principle) the OAM of light offers unlimited expansion to high-dimensionality , it has become a natural selection towards the new generation of encoding techniques [85][86][87][88][89][90][91][92][93][94][95][96][97][98][99][100][101]. Several ways of preparing OAM states have been studied, such as the use of spatial light modulators [102] or q-plates [52].…”

Special Issue on Novel Insights into Orbital Angular Momentum Beams: From Fundamentals, Devices to Applications

“…Another review paper, focusing on tunable OAM generation, is contributed from Prof. Wu's group [26]. The authors classify the tunable OAM mode generation methods into three categories, according to the OAM and polarization states.…”

Evolution on spatial patterns of structured laser beams: from spontaneous organization to multiple transformations

“…Such beams have brought various breakthroughs to many fields, including imaging, 24 , 25 microscopy, 26 , 27 metrology, 28 – 30 communication, 31 – 33 optical trapping, 34 – 36 and quantum information processing 37 – 39 In the most recent five years, the number of reviews on structured light has boomed, with the majority of reviews focusing on technical-level research into the phenomenon, 40 – 54 such as the generation and detection technology of structured light, 44 , 45 application in the field of optical trapping 46 , 47 and anti-turbulence, 48 progress in optical vortices 49 – 51 and higher-dimensional structured light, 52 as well as research on structured light in flat optics 53 and nonlinear optics 54 . In contrast, there have been few studies on the evolution of the investigations and corresponding understandings of the pattern formation of structured laser beams.…”