Hollow core optical fibres with comparable attenuation to silica fibres between 600 and 1100 nm

AbstractFor over 50 years, pure or doped silica glass optical fibres have been an unrivalled platform for the transmission of laser light and optical data at wavelengths from the visible to the near infra-red. Rayleigh scattering, arising from frozen-in density fluctuations in the glass, fundamentally limits the minimum attenuation of these fibres and hence restricts their application, especially at shorter wavelengths. Guiding light in hollow (air) core fibres offers a potential way to overcome this insurmountable attenuation limit set by the glass’s scattering, but requires reduction of all the other loss-inducing mechanisms. Here we report hollow core fibres, of nested antiresonant design, with losses comparable or lower than achievable in solid glass fibres around technologically relevant wavelengths of 660, 850, and 1060 nm. Their lower than Rayleigh scattering loss in an air-guiding structure offers the potential for advances in quantum communications, data transmission, and laser power delivery.

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Topological pruning enables ultra-low Rayleigh scattering in pressure-quenched silica glass

npj Computational Materials ◽

10.1038/s41524-020-00408-1 ◽

2020 ◽

Vol 6 (1) ◽

Author(s):

Yongjian Yang ◽

Osamu Homma ◽

Shingo Urata ◽

Madoka Ono ◽

John C. Mauro

Keyword(s):

Silica Glass ◽

Rayleigh Scattering ◽

Transmission Loss ◽

Density Fluctuations ◽

Physical Models ◽

Silica Network ◽

Fictive Temperature ◽

Scattering Loss ◽

The Past ◽

Optical Applications

Abstract Silica glass is the most indispensable material in optical communication applications due to its superior optical properties. The transmission loss of silica glass has been reduced over the past 30 years by continuous efforts toward decreasing density fluctuations by lowering of fictive temperature, e.g., through improvements in processing or doping. A recent study has shown that shrinkage of structural voids by hot compression is a promising way to further decrease the loss. However, an atomic understanding of the pressure effect is still lacking. Here, using molecular simulations, we connect the void shrinkage to topological pruning of silica network. Two physical models predict that the Rayleigh scattering loss of pressure-quenched silica glass can be reduced by >50% when the glass is quenched at an appropriate pressure (4 GPa in our simulation). Our studies are consistent with available experimental results and demonstrate topologically optimized structure can give desirable properties for optical applications of silica as well as other glasses with similar network structure.

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Freely scalable and reconfigurable optical hardware for deep learning

Scientific Reports ◽

10.1038/s41598-021-82543-3 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Liane Bernstein ◽

Alexander Sludds ◽

Ryan Hamerly ◽

Vivienne Sze ◽

Joel Emer ◽

...

Keyword(s):

Neural Network ◽

Energy Consumption ◽

Data Transfer ◽

Power Delivery ◽

Optical Data ◽

Optical Multicast ◽

Optical Neural Network ◽

Fully Connected ◽

Management Power

AbstractAs deep neural network (DNN) models grow ever-larger, they can achieve higher accuracy and solve more complex problems. This trend has been enabled by an increase in available compute power; however, efforts to continue to scale electronic processors are impeded by the costs of communication, thermal management, power delivery and clocking. To improve scalability, we propose a digital optical neural network (DONN) with intralayer optical interconnects and reconfigurable input values. The path-length-independence of optical energy consumption enables information locality between a transmitter and a large number of arbitrarily arranged receivers, which allows greater flexibility in architecture design to circumvent scaling limitations. In a proof-of-concept experiment, we demonstrate optical multicast in the classification of 500 MNIST images with a 3-layer, fully-connected network. We also analyze the energy consumption of the DONN and find that digital optical data transfer is beneficial over electronics when the spacing of computational units is on the order of $$>10\,\upmu $$ > 10 μ m.

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Study of Birefringence and Mode Field for Hollow-Core Photonic Bandgap Fiber

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.609-610.324 ◽

2014 ◽

Vol 609-610 ◽

pp. 324-329

Author(s):

Li Shuang Feng ◽

Wen Shuai Song ◽

Xiao Yuan Ren

Keyword(s):

Field Distribution ◽

Photonic Bandgap ◽

Surface Mode ◽

Hollow Core ◽

The Finite Element Method ◽

Core Mode ◽

Photonic Bandgap Fiber ◽

Mode Field ◽

Air Core ◽

Polarization Maintaining

Since the Appearance of Hollow-Core Photonic Bandgap Fiber (HC-PBF), it was Widely Concerned for its Excellent Characteristics. in Order to Study the Characteristics of the HC-PBF that can be Used in Resonator Fiber Optic Gyros (R-Fogs), the Model Structure of a Polarization-Maintaining HC-PBF was Built and its Performance was Simulated by Using the Finite Element Method (FEM). its Mode Field Distribution and Birefringence Characteristics were Obtained. the Influences of the Air Core and Cladding Structures on the Mode Field Distribution and Birefringence were Simulated and Analyzed Further. the Result Showed that there are both Core Mode and Surface Mode in the Structure we Built. by Adding Scattering Points into the Fiber Core, the Surface Mode can be Significantly Suppressed. by Matching the Size of Core and Air Holes around the Core, a Birefringence up to 8*10-4 were Obtained.

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Low-loss ARROW waveguide with rectangular hollow core and rectangular low-density polyethylene/air reflectors for terahertz waves

Journal of Nonlinear Optical Physics & Materials ◽

10.1142/s0218863518500297 ◽

2018 ◽

Vol 27 (03) ◽

pp. 1850029 ◽

Cited By ~ 1

Author(s):

Henri P. Uranus ◽

B. M. A. Rahman

Keyword(s):

Refractive Index ◽

Low Density Polyethylene ◽

Low Density ◽

Hollow Core ◽

Terahertz Waves ◽

Low Loss ◽

Leakage Loss ◽

Crystal Fiber ◽

Air Core ◽

The Waves

Designing low-loss waveguides for terahertz waves is challenging as most materials are very lossy in this frequency band. Most scientists simply consider transmitting the waves through low-loss air, which however also has its own difficulties as index-guiding is not possible. In this paper, we report on the design of low-loss waveguides for terahertz waves and associated results by using a finite element leaky mode solver. These results show that waveguides designed using ARROW (anti-resonant reflecting optical waveguide) approach yield a low combined absorption and leakage loss down to only 0.05[Formula: see text]dB/cm for the q-TE[Formula: see text] fundamental mode using realistic values of refractive index at 1 THz operating frequency. The structure employs rectangular hollow-core and low-density polyethylene/air anti-resonant reflecting bilayers, which can be easily fabricated. These results are compared with those of other structures, i.e., a photonic crystal fiber-like structures using the same materials with rectangular holes, which is shown to give a higher loss of 3[Formula: see text]dB/cm and a suspended air-core waveguide with TOPAS vein offering a loss of 1[Formula: see text]dB/cm.

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Estimation of Rayleigh scattering loss in a double-clad photonic crystal fiber

Optical and Quantum Electronics ◽

10.1007/s11082-018-1482-4 ◽

2018 ◽

Vol 50 (5) ◽

Cited By ~ 3

Author(s):

Milan S. Kovacevic ◽

Ljubica Kuzmanovic ◽

Alexandar Djordjevich

Keyword(s):

Photonic Crystal ◽

Photonic Crystal Fiber ◽

Rayleigh Scattering ◽

Scattering Loss ◽

Crystal Fiber

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Diode pumped visible Dy3+-doped silica fiber laser: Ge-co-doping effects on lasing efficiency and photodarkening

Applied Physics Express ◽

10.35848/1882-0786/ac3d1d ◽

2021 ◽

Author(s):

Tomoya Okazaki ◽

Chiaki Otsuka ◽

Edson Haruhico Sekiya ◽

Kota Kawai ◽

Masato Mizusaki ◽

...

Keyword(s):

Slope Efficiency ◽

Rayleigh Scattering ◽

Maximum Output Power ◽

Silica Fiber ◽

Maximum Output ◽

Laser Oscillation ◽

Scattering Loss ◽

Co Doping ◽

Doping Effects ◽

Diode Pumped

Abstract We present the first demonstration of visible laser oscillation in the Dy3+-doped silica fiber pumped by a 451nm InGaN laser diode. It was found that Ge-co-doping plays the following important roles of laser oscillation: (1) to reduce the Rayleigh scattering loss, (2) to suppress the X-ray-induced and pump-induced photodarkening (PD), and (3) to increase lasing slope efficiency. In a fiber with 0.46wt% Dy, 1.8 wt% Ge, and 0.54wt% Al, the slope efficiency is 22.0 % at 582.5 nm, and the maximum output power is 18.4 mW.

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Antiresonant reflection and inhibited coupling in hollow-core square lattice optical fibres

Optics Express ◽

10.1364/oe.16.005642 ◽

2008 ◽

Vol 16 (8) ◽

pp. 5642 ◽

Cited By ~ 48

Author(s):

Alexander Argyros ◽

Sergio G. Leon-Saval ◽

Jarryd Pla ◽

Andrew Docherty

Keyword(s):

Square Lattice ◽

Optical Fibres ◽

Hollow Core

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Optical Fibres for Condition Monitoring of Railway Infrastructure—Encouraging Data Source or Errant Effort?

Applied Sciences ◽

10.3390/app10176016 ◽

2020 ◽

Vol 10 (17) ◽

pp. 6016 ◽

Cited By ~ 1

Author(s):

Ivan Vidovic ◽

Stefan Marschnig

Keyword(s):

Rayleigh Scattering ◽

Acoustic Vibration ◽

Optical Fibres ◽

Maintenance Planning ◽

Root Cause ◽

Railway Tracks ◽

Railway Infrastructure ◽

Vibration Sensing ◽

Data Source ◽

Asset Data

The condition of railway infrastructure is currently assessed by track recording cars, wayside equipment, onboard monitoring techniques and visual inspections. These data sources deliver valuable information for infrastructure managers on the asset’s condition but are mostly carried out in time-based intervals. This paper examines the potential of fibre optic cables, which are already installed in cable troughs alongside railway tracks, to monitor railway infrastructure conditions. The sensing technique, known as distributed acoustic/vibration sensing (DAS/DVS), relies on the effect of Rayleigh scattering and transforms the optical fibre into an array of “virtual microphones” in the thousands. This sensing method has the ability to be used over long distances and thus provide information about the events taking place in the proximity of the monitored asset in real-time. This study outlines the potential of DAS for the identification of different track conditions and isolated track defects. The results are linked to asset data of the infrastructure manager to identify the root cause of the detected signal anomalies and pattern. A methodology such as this allows for condition-based and component-specific maintenance planning and execution and avoids the installation of additional sensors. DAS can pave the way toward a permanent and holistic assessment of railway tracks.

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