1,317 research outputs found
The Orbital Angular Momentum of Light for Ultra-High Capacity Data Centers
The potential of orbital angular momentum (OAM) of light in data center scenarios is presented. OAMs can be exploited for short reach ultra-high bit rate fiber links and as additional multiplexing domain in transparent ultra-high capacity optical switches. Recent advances on OAM integrated photonic technology are also reported. Finally demonstration of OAM-based fiber links (aggregate throughput 17.9 Tb/s) and two layers OAM-WDM-based optical switches are presented exploiting OAM integrated components and demonstrating the achievable benefits in terms of size, weight and power consumption (SWaP) compared to different technologies
Limitations to the determination of a Laguerre-Gauss spectrum via projective, phase-flattening measurement
One of the most widely used techniques for measuring the orbital angular
momentum components of a light beam is to flatten the spiral phase front of a
mode, in order to couple it to a single-mode optical fiber. This method,
however, suffers from an efficiency that depends on the orbital angular
momentum of the initial mode and on the presence of higher order radial modes.
The reason is that once the phase has been flattened, the field retains its
ringed intensity pattern and is therefore a nontrivial superposition of purely
radial modes, of which only the fundamental one couples to a single mode
optical fiber. In this paper, we study the efficiency of this technique both
theoretically and experimentally. We find that even for low values of the OAM,
a large amount of light can fall outside the fundamental mode of the fiber, and
we quantify the losses as functions of the waist of the coupling beam of the
orbital angular momentum and radial indices. Our results can be used as a tool
to remove the efficiency bias where fair-sampling loopholes are not a concern.
However, we hope that our study will encourage the development of better
detection methods of the orbital angular momentum content of a beam of light.Comment: 5 pages, 4 figure
Twisted Light Experimental
The goal of this project is to first present a detailed explanation and analysis of light with Orbital Angular Momentum (OAM), and then determine the optimal waveguide profile for the transfer of light with OAM through an optical fiber. In particular, the ring index variation fiber was studied. The explanation describes different laser modes and what it means for light to have OAM. This was accomplished by exploring the available literature on the topic. The analysis involves solving Maxwell\u27s equations for a three-layer fiber in order to determine a characteristic equation, the solution of which can be used to make modal charts
Compact and high-performance vortex mode sorter for multi-dimensional multiplexed fiber communication systems
With the amplitude, time, wavelength/frequency, phase, and polarization/spin parameter dimensions of the light wave/photon almost fully utilized in both classical and quantum photonic information systems, orbital angular momentum (OAM) carried by optical vortex modes is regarded as a new modal parameter dimension for further boosting the capacity and performance of the systems. To exploit the OAM mode space for such systems, stringent performance requirements on a pair of OAM mode multiplexer and demultiplexer (also known as mode sorters) must be met. In this work, we implement a newly discovered optical spiral transformation to achieve a low-cross-Talk, wide-opticalbandwidth, polarization-insensitive, compact, and robust OAM mode sorter that realizes the desired bidirectional conversion between seven co-Axial OAM modes carried by a ring-core fiber and seven linearly displaced Gaussian-like modes in parallel single-mode fiber channels. We further apply the device to successfully demonstrate high-spectralefficiency and high-capacity data transmission in a 50-km OAM fiber communication link for the first time, in which a multi-dimensional multiplexing scheme multiplexes eight orbital-spin vortex mode channels with each mode channel simultaneously carrying 10 wavelength-division multiplexing channels, demonstrating the promising potential of both the OAM mode sorter and the multi-dimensional multiplexed OAM fiber systems enabled by the device. Our results pave the way for futureOAM-based multi-dimensional communication systems
Geometric phase for twisted light
Polarization vectors of light traveling in a coiled optical fiber rotate
around its propagating axis even in the absence of birefringence. This rotation
was usually explained due to the Pancharatnam-Berry phase of spin-1 photons.
Here, we use a purely geometric method to understand this rotation. We show
that similar geometric rotations also exist for twisted light carrying orbital
angular momentum (OAM). The corresponding geometric phase can be applied in
photonic OAM-state-based quantum computation and quantum sensing.Comment: 6 pages and 4 figure
Enhanced spin orbit interaction of light in highly confining optical fibers for mode division multiplexing
Light carries both orbital angular momentum (OAM) and spin angular momentum (SAM), related to wavefront rotation and polarization, respectively. These are usually approximately independent quantities, but they become coupled by light's spin-orbit interaction (SOI) in certain exotic geometries and at the nanoscale. Here we reveal a manifestation of strong SOI in fibers engineered at the micro-scale and supporting the only known example of propagating light modes with non-integer mean OAM. This enables propagation of a record number (24) of states in a single optical fiber with low cross-talk (purity > 93%), even as tens-of-meters long fibers are bent, twisted or otherwise handled, as fibers are practically deployed. In addition to enabling the investigation of novel SOI effects, these light states represent the first ensemble with which mode count can be potentially arbitrarily scaled to satisfy the exponentially growing demands of high-performance data centers and supercomputers, or telecommunications network nodes
Orbital Angular Momentum Waves: Generation, Detection and Emerging Applications
Orbital angular momentum (OAM) has aroused a widespread interest in many
fields, especially in telecommunications due to its potential for unleashing
new capacity in the severely congested spectrum of commercial communication
systems. Beams carrying OAM have a helical phase front and a field strength
with a singularity along the axial center, which can be used for information
transmission, imaging and particle manipulation. The number of orthogonal OAM
modes in a single beam is theoretically infinite and each mode is an element of
a complete orthogonal basis that can be employed for multiplexing different
signals, thus greatly improving the spectrum efficiency. In this paper, we
comprehensively summarize and compare the methods for generation and detection
of optical OAM, radio OAM and acoustic OAM. Then, we represent the applications
and technical challenges of OAM in communications, including free-space optical
communications, optical fiber communications, radio communications and acoustic
communications. To complete our survey, we also discuss the state of art of
particle manipulation and target imaging with OAM beams
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