The metod of reducing measurement error of the propagation delays in optical elements and optical fibers

2019 ◽  
Author(s):  
Deykun AV ◽  
Kolmogorov OV
Keyword(s):  
Measurement Error ◽  
Optical Fibers ◽  
Optical Elements ◽  
Propagation Delays

scholarly journals Design of Spatial-Mode (De)Multiplexer for Few-Mode Fibers Based on a Cyclically Used Michelson-Like Interferometer

2020 ◽  
Vol 10 (23) ◽  
pp. 8584
Author(s):  
Xesús Prieto-Blanco ◽  
Carlos Montero-Orille ◽  
Vicente Moreno de Las Cuevas ◽  
María C. Nistal ◽  
Dolores Mouriz ◽  
...  
Keyword(s):  
Optical Fibers ◽  
Efficient Method ◽  
Optical Communications ◽  
Data Rate ◽  
Phase Plate ◽  
Spatial Mode ◽  
Optical Elements ◽  
Polarization Insensitive ◽  
Elliptical Core

Few mode optical fibers are a promising way to continue increasing the data rate in optical communications. However, an efficient method to launch and extract separately each mode is essential. The design of a interferometric spatial mode (de)multiplexer for few mode optical fibers is presented. It is based on a single Michelson-like interferometer which consists of standard optical elements and has a reflective image inverter in one arm. Particular care has been taken in its design so that both polarizations behave the same. Moreover, this interferometer can process several pairs of modes simultaneously. The multiplexer also consists of: a phase plate, focusing optics at both ports of the interferometer and elliptical core fibers to recirculate some outputs. It can multiplex ten spatial and polarization modes and it presents low losses and no intrinsic crosstalk between modes. Additionally, it is polarization insensitive, achromatic, compact and inexpensive. The same system can work as a demultiplexer when used in reverse. In this case, both the losses and the crosstalk remain very low. Similar designs that perform other functions, like an add-drop mode multiplexing, are also suggested.

scholarly journals Novel Model for the Angle and Skewness Dependent Transmission Behavior of Step-Index Polymer Optical Fiber

Fibers ◽  
2018 ◽  
Vol 6 (3) ◽  
pp. 65 ◽  
Author(s):  
Thomas Becker ◽  
Rainer Engelbrecht ◽  
Bernhard Schmauss
Keyword(s):  
Measurement Error ◽  
Optical Fibers ◽  
Optical Transmission ◽  
Real Data ◽  
Transmission System ◽  
Phase Response ◽  
Polymer Optical Fiber ◽  
Step Index ◽  
The Impact ◽  
Novel Model

Step-index polymer optical fibers (SI-POFs) are deployed in both sensing and data transmission systems. The optical transmission behavior of these fibers is complex and affected by intrinsic influences like modal dispersion, scattering and attenuation as well as extrinsic influences like the launching condition and the angular sensitivity of the receiver. Since a proper modeling of the transmission behavior is important in order to evaluate the suitability of the fiber for a specific application, we present a novel model for step-index multi-mode fibers (SI-MMFs) which considers all the previously mentioned impacts. Furthermore, the model differentiates scattering and attenuation for propagating rays not only by their propagating angle θ z but also by the skewness θ ϕ . It is therefore possible to distinguish between guided, tunneling and refracted modes. The model uses scatter and attenuation data from previously published measurements of an SI-POF and computes the impulse response of the transmission system which is transferred to the frequency domain to derive the amplitude and phase response. A possible application for SI-POF is the length or strain measurement of the fiber by measuring the phase of a harmonically modulated signal. These sensors rely on a linear relation between the length of the fiber and the phase of the modulated signal. We demonstrate the application of the model by simulating the length measurement error that occurs for these sensors by obtaining the phase response for the corresponding optical transmission system. Furthermore, we will demonstrate the flexibility of the model by varying several influences including the excitation of different mode categories and evaluate the impact on the measurement error. Finally, we compare the simulated length error derived from the model to real data obtained from a cutback measurement. An implementation of the model, which was used for all simulations in this paper, is publicly available.

Near-Zero Shift Attachment for Optoelectronic Components

2011 ◽  
Vol 2011 (1) ◽  
pp. 001058-001066
Author(s):  
Roy J. Bourcier
Keyword(s):  
Optical Fibers ◽  
High Performance ◽  
Coupling Efficiency ◽  
Single Mode ◽  
Optical Coupling ◽  
Free Space Optical ◽  
Optical Elements ◽  
Uv Curable ◽  
Design Concepts ◽  
Process Elements

High performance laser-based optoelectronic devices commonly feature the use of free-space optical coupling between the laser diode and optical elements such as filters, secondary harmonic generators and optical fibers. A critical challenge in the assembly of such components is maintaining the required optical alignment precision during attachment of the optical subcomponents to a common platform. In the case of devices based on single mode waveguides, the post-attach shift must often be held to less than a few hundred nanometers to achieve the desired optical coupling efficiency. Historically, these tight tolerances have required the use of costly post-work operations such as laser hammering or re-bend to achieve performance objectives. Over the course of designing several such optoelectronic components, we have used and developed a variety of design concepts and assembly processes which have allowed us to achieve these demanding tolerances, often without the use of post-work. UV-curable structural adhesives and Nd:YAG laser spot welding have been used, individually and in combination, to perform the required sub-micron optomechanical attachments. Several approaches which have been successfully used will be described and their relative merits will be compared. In addition, key design and process elements which can impact post-attach shift will be discussed.

scholarly journals A Review on Metasurface: From Principle to Smart Metadevices

2021 ◽  
Vol 8 ◽  
Author(s):  
Jie Hu ◽  
Sankhyabrata Bandyopadhyay ◽  
Yu-hui Liu ◽  
Li-yang Shao
Keyword(s):  
Optical Fibers ◽  
Electromagnetic Waves ◽  
Berry Phase ◽  
Practical Application ◽  
Optical Elements ◽  
The Past ◽  
Reflection And Refraction ◽  
Anomalous Reflection ◽  
Electric And Magnetic Fields ◽  
Dielectric Structures

Metamaterials are composed of periodic subwavelength metallic/dielectric structures that resonantly couple to the electric and magnetic fields of the incident electromagnetic waves, exhibiting unprecedented properties which are most typical within the context of the electromagnetic domain. However, the practical application of metamaterials is found challenging due to the high losses, strong dispersion associated with the resonant responses, and the difficulty in the fabrication of nanoscale 3D structures. The optical metasurface is termed as 2D metamaterials that inherent all of the properties of metamaterials and also provide a solution to the limitation of the conventional metamaterials. Over the past few years, metasurfaces; have been employed for the design and fabrication of optical elements and systems with abilities that surpass the performance of conventional diffractive optical elements. Metasurfaces can be fabricated using standard lithography and nanoimprinting methods, which is easier campared to the fabrication of the counterpart 3 days metamaterials. In this review article, the progress of the research on metasurfaces is illustrated. Concepts of anomalous reflection and refraction, applications of metasurfaces with the Pancharatanm-Berry Phase, and Huygens metasurface are discussed. The development of soft metasurface opens up a new dimension of application zone in conformal or wearable photonics. The progress of soft metasurface has also been discussed in this review. Meta-devices that are being developed with the principle of the shaping of wavefronts are elucidated in this review. Furthermore, it has been established that properties of novel optical metasurface can be modulated by the change in mechanical, electrical, or optical stimuli which leads to the development of dynamic metasurface. Research thrusts over the area of tunable metasurface has been reviewed in this article. Over the recent year, it has been found that optical fibers and metasurface are coagulated for the development of optical devices with the advantages of both domains. The metasurface with lab-on fiber-based devices is being discussed in this review paper. Finally, research trends, challenges, and future scope of the work are summarized in the conclusion part of the article.‬‬‬‬‬‬‬

Reducing the measurement error of signal propagation delays using an optical reflectometer with picosecond resolution

2020 ◽  
pp. 30-34
Author(s):  
O.V. Kolmogorov ◽  
A.N. Shchipunov ◽  
O.V. Denisenko ◽  
S.S. Donchenko ◽  
D.V. Prokhorov ◽  
...  
Keyword(s):  
Optical Fiber ◽  
Optical Fibers ◽  
Signal Propagation ◽  
Propagation Delay ◽  
Total Delay ◽  
Reference Equipment ◽  
Measuring Installation ◽  
Additive Component ◽  
Propagation Delays ◽  
Optical Reflectometer

The problems requiring high-precision measurements of signal propagation delays in optical fibers are considered. Design features of a pulsed optical reflectometer with a picosecond resolution designed for measuring propagation delays of a signal are considered. It is shown that the error of such a reflectometer includes the additive and multiplicative components. A method for determining the additive component of the optical reflectometer error based on measurements of signal delays introduced by individual optical fiber coils and the total delay introduced by series-connected coils is proposed. The requirements to the measurement conditions are formulated and the results of the error estimation of the proposed method are presented. To exclude the multiplicative component of the reflectometer error, a method for determining corrections to the reflectometer readings is proposed. The method is based on measuring the propagation delays of the signal in the coils of the optical fiber, first using reference equipment (installation for measuring the propagation delay of the signal), and then using an optical reflectometer, and then calculating the differences of the obtained measurement results. The scheme of installation for measurements of a propagation delay of signal in a coil of optical fiber is presented, the principle of operation of measuring installation is described. The results of the estimation of the error in determining the corrections to the reflectometer readings by the proposed method are presented. It is shown that the exclusion of the additive and multiplicative components of the error will reduce the error of optical reflectometers to values less than ± 100 ps.

Reducing the Measurement Error of Signal Propagation Delays Using an Optical Reflectometer with Picosecond Resolution

2020 ◽  
Vol 63 (1) ◽  
pp. 29-33
Author(s):  
O. V. Kolmogorov ◽  
A. N. Shchipunov ◽  
O. V. Denisenko ◽  
S. S. Donchenko ◽  
D. V. Prokhorov ◽  
...  
Keyword(s):  
Measurement Error ◽  
Signal Propagation ◽  
Propagation Delays ◽  
Optical Reflectometer

scholarly journals A Comprehensive Survey on Nanophotonics Neural Networks

2021 ◽  
Author(s):  
Konstantinos Demertzis* ◽  
Georgios Papadopoulos ◽  
Lazaros Iliadis ◽  
Lykourgos Magafas
Keyword(s):  
Neural Networks ◽  
Optical Fibers ◽  
Training Methods ◽  
Optical Elements ◽  
Neuromorphic Circuits ◽  
Simultaneous Processing ◽  
Comprehensive Survey ◽  
Optical Activation ◽  
Computational Systems ◽  
Optical Circuits

: In the last years, materializations of neuromorphic circuits based on nanophotonic arrangements have been proposed, which contain complete optical circuits, laser, photodetectors, photonic crystals, optical fibers, flat waveguides, and other passive optical elements of nanostructured materials, which eliminate the time of simultaneous processing of big groups of data, taking advantage of the quantum perspective and thus highly increasing the potentials of contemporary intelligent computational systems. This article is an effort to record and study the research that has been conducted concerning the methods of development and materialization of neuromorphic circuits of Neural Networks of nanophotonic arrangements. In particular, an investigative study of the methods of developing nanophotonic neuromorphic processors, their originality in neuronic architectural structure, their training methods and their optimization has been realized along with the study of special issues such as optical activation functions and cost functions.

Near-field scanning optical microscopy

1986 ◽  
Vol 44 ◽  
pp. 642-643
Author(s):  
E. Betzig ◽  
A. Harootunian ◽  
M. Isaacson ◽  
A. Lewis
Keyword(s):  
Near Field ◽  
Optical Microscope ◽  
Visible Radiation ◽  
Field Methods ◽  
Optical Elements ◽  
Optical Region ◽  
Order Of Magnitude ◽  
Nondestructive Imaging ◽  
Scanning Optical Microscopy ◽  
Near Field Scanning

In general, conventional methods of optical imaging are limited in spatial resolution by either the wavelength of the radiation used or by the aberrations of the optical elements. This is true whether one uses a scanning probe or a fixed beam method. The reason for the wavelength limit of resolution is due to the far field methods of producing or detecting the radiation. If one resorts to restricting our probes to the near field optical region, then the possibility exists of obtaining spatial resolutions more than an order of magnitude smaller than the optical wavelength of the radiation used. In this paper, we will describe the principles underlying such "near field" imaging and present some preliminary results from a near field scanning optical microscope (NS0M) that uses visible radiation and is capable of resolutions comparable to an SEM. The advantage of such a technique is the possibility of completely nondestructive imaging in air at spatial resolutions of about 50nm.

Characterization of Rh/Si multilayer structure by HREM and HAADF

1992 ◽  
Vol 50 (1) ◽  
pp. 122-123
Author(s):  
Y. Cheng ◽  
J. Liu ◽  
M.B. Stearns ◽  
D.G. Steams
Keyword(s):  
Normal Incidence ◽  
High Resolution Electron Microscopy ◽  
X Rays ◽  
Beam Direction ◽  
Cross Sectional ◽  
Optical Elements ◽  
Resolution Electron ◽  
Point To Point ◽  
Better Than

The Rh/Si multilayer (ML) thin films are promising optical elements for soft x-rays since they have a calculated normal incidence reflectivity of ∼60% at a x-ray wavelength of ∼13 nm. However, a reflectivity of only 28% has been attained to date for ML fabricated by dc magnetron sputtering. In order to determine the cause of this degraded reflectivity the microstructure of this ML was examined on cross-sectional specimens with two high-resolution electron microscopy (HREM and HAADF) techniques.Cross-sectional specimens were made from an as-prepared ML sample and from the same ML annealed at 298 °C for 1 and 100 hours. The specimens were imaged using a JEM-4000EX TEM operating at 400 kV with a point-to-point resolution of better than 0.17 nm. The specimens were viewed along Si [110] projection of the substrate, with the (001) Si surface plane parallel to the beam direction.

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