206 research outputs found
Transverse load and orientation measurement with multicore fiber Bragg gratings
We demonstrate the sensitivity of Bragg gratings in a multicore fiber to transverse load. The Bragg peaks are split because of stress-induced birefringence, the magnitude of which depends upon the load and grating position relative to the load axis. Experiments show that a set of gratings in a four-core fiber can measure a load axis angle to ±5° and a load magnitude to ±15 N m-1 up to 2500 N m-1. We consider alternative designs of multicore fiber for optimal load sensing and compare experimental and modeled data
In-situ multicore fibre-based pH mapping through obstacles in integrated microfluidic devices
Microfluidic systems with integrated sensors are ideal platforms to study and
emulate processes such as complex multiphase flow and reactive transport in
porous media, numerical modeling of bulk systems in medicine, and in
engineering. Existing commercial optical fibre sensing systems used in
integrated microfluidic devices are based on single-core fibres, limiting the
spatial resolution in parameter measurements in such application scenarios.
Here, we propose a multicore fibre-based pH system for in-situ pH mapping with
tens of micrometer spatial resolution in microfluidic devices. The
demonstration uses custom laser-manufactured glass microfluidic devices (called
further micromodels) consisting of two round ports. The micromodels comprise
two lintels for the injection of various pH buffers and an outlet. The two-port
system facilitates the injection of various pH solutions using independent
pressure pumps. The multicore fibre imaging system provides spatial information
about the pH environment from the intensity distribution of fluorescence
emission from the sensor attached to the fibre end facet, making use of the
cores in the fibre as independent measurement channels. As a proof-of-concept,
we performed pH measurements in micromodels through obstacles (glass and rock
beads), showing that the particle features can be clearly distinguishable from
the intensity distribution from the fibre sensor.Comment: 12 pages of main draft with 10 figures, 2 pages of supplementary
information with 3 figures. Total 14 page
High-speed PAM4-based Optical SDM Interconnects with Directly Modulated Long-wavelength VCSEL
This paper reports the demonstration of high-speed PAM-4 transmission using a
1.5-{\mu}m single-mode vertical cavity surface emitting laser (SM-VCSEL) over
multicore fiber with 7 cores over different distances. We have successfully
generated up to 70 Gbaud 4-level pulse amplitude modulation (PAM-4) signals
with a VCSEL in optical back-to-back, and transmitted 50 Gbaud PAM-4 signals
over both 1-km dispersion-uncompensated and 10-km dispersion-compensated in
each core, enabling a total data throughput of 700 Gbps over the 7-core fiber.
Moreover, 56 Gbaud PAM-4 over 1-km has also been shown, whereby unfortunately
not all cores provide the required 3.8 10 bit error rate (BER)
for the 7% overhead-hard decision forward error correction (7% OH HDFEC). The
limited bandwidth of the VCSEL and the adverse chromatic dispersion of the
fiber are suppressed with pre-equalization based on accurate end-to-end channel
characterizations. With a digital post-equalization, BER performance below the
7% OH-HDFEC limit is achieved over all cores. The demonstrated results show a
great potential to realize high-capacity and compact short-reach optical
interconnects for data centers.Comment: 7 pages, accepted to publication in 'Journal of Lightwave Technology
(JLT
Two-Dimensional Displacement Sensor Based on Plastic Optical Fibers
An inexpensive fiber-based displacement sensor for two-dimensional crack monitoring is proposed and analyzed. The device is packaged as conventional crack monitoring gages based on sliding plates and exploits the dependence of the transmitted power between facing optical fibers with the displacement. The use of multi-core polymeric fibers with high numerical aperture allows a compact form factor and simplifies the sensor assembly. The position detection algorithm has been optimized through simulations; then experimental tests have shown a good agreement with simulations and have proved that even with simplified layout and artisanal realization the sensor can measure displacements in a square area of 3 mm by 3 mm with an uncertainty better than 0.05 m
Power system applications of fiber optic sensors
This document is a progress report of work done in 1985 on the Communications and Control for Electric Power Systems Project at the Jet Propulsion Laboratory. These topics are covered: Electric Field Measurement, Fiber Optic Temperature Sensing, and Optical Power transfer. Work was done on the measurement of ac and dc electric fields. A prototype sensor for measuring alternating fields was made using a very simple electroscope approach. An electronic field mill sensor for dc fields was made using a fiber optic readout, so that the entire probe could be operated isolated from ground. There are several instances in which more precise knowledge of the temperature of electrical power apparatus would be useful. This report describes a number of methods whereby the distributed temperature profile can be obtained using a fiber optic sensor. The ability to energize electronics by means of an optical fiber has the advantage that electrical isolation is maintained at low cost. In order to accomplish this, it is necessary to convert the light energy into electrical form by means of photovoltaic cells. JPL has developed an array of PV cells in gallium arsenide specifically for this purpose. This work is described
Power‐Over‐Fiber Applications for Telecommunications and for Electric Utilities
Beyond telecommunications, optical fibers can also transport optical energy to powering electric or electronic devices remotely. This technique is called power over fiber (PoF). Besides the advantages of optical fiber (immunity to electromagnetic interferences and electrical insulation), the employment of a PoF scheme can eliminate the energy supplied by metallic cable and batteries located at remote sites, improving the reliability and the security of the system. Smart grid is a green field where PoF can be applied. Experts see smart grid as the output to a new technological level seeks to incorporate extensively technologies for sensing, monitoring, information technology, and telecommunications for the best performance electrical network. On the other hand, in telecommunications, PoF can be used in applications, such as remote antennas and extenders for passive optical networks (PONs). PoF can make them virtually passives. We reviewed the PoF concept, its main elements, technologies, and applications focusing in access networks and in smart grid developments made by the author’s research group
Organ Shape Sensing using Pneumatically Attachable Flexible Rails in Robotic-Assisted Laparoscopic Surgery
In robotic-assisted partial nephrectomy, surgeons remove a part of a kidney
often due to the presence of a mass. A drop-in ultrasound probe paired to a
surgical robot is deployed to execute multiple swipes over the kidney surface
to localise the mass and define the margins of resection. This sub-task is
challenging and must be performed by a highly skilled surgeon. Automating this
sub-task may reduce cognitive load for the surgeon and improve patient
outcomes. The overall goal of this work is to autonomously move the ultrasound
probe on the surface of the kidney taking advantage of the use of the
Pneumatically Attachable Flexible (PAF) rail system, a soft robotic device used
for organ scanning and repositioning. First, we integrate a shape-sensing
optical fibre into the PAF rail system to evaluate the curvature of target
organs in robotic-assisted laparoscopic surgery. Then, we investigate the
impact of the stiffness of the material of the PAF rail on the curvature
sensing accuracy, considering that soft targets are present in the surgical
field. Finally, we use shape sensing to plan the trajectory of the da Vinci
surgical robot paired with a drop-in ultrasound probe and autonomously generate
an Ultrasound scan of a kidney phantom.Comment: 9 pages, 11 figure
Multi-core Fiber Technology
Traditional single-mode fiber capacity issues will be mitigated by using space-division multiplexing in future 5G, IoT, and M2M networks. Multi-core fibers are expected as a good candidate for overcoming the capacity limit of a current optical communication system. This chapter describes the recent progress on the Multi-core fibers technology for the application of high capacity space-division multiplexing to be utilized for long-distance transmission systems. Further various optical approaches that enable key functions are discussed, including SDM MUX/DeMUX, switches, transceivers to enable next generation optical network. Moreover, issues like crosstalk, non-linearity is a potential limitation on the achievable data-rates in optical fiber transmission systems using multi-core fibers will be discussed
Overcoming challenges in large-core SI-POF-based system-level modeling and simulation
The application areas for plastic optical fibers such as in-building or aircraft networks usually have tight power budgets and require multiple passive components. In addition, advanced modulation formats are being considered for transmission over plastic optical fibers (POFs) to increase spectral efficiency. In this scenario, there is a clear need for a flexible and dynamic system-level simulation framework for POFs that includes models of light propagation in POFs and the components that are needed to evaluate the entire system performance. Until recently, commercial simulation software either was designed specifically for single-mode glass fibers or modeled individual guided modes in multimode fibers with considerable detail, which is not adequate for large-core POFs where there are millions of propagation modes, strong mode coupling and high variability. These are some of the many challenges involved in the modeling and simulation of POF-based systems. Here, we describe how we are addressing these challenges with models based on an intensity-vs-angle representation of the multimode signal rather than one that attempts to model all the modes in the fiber. Furthermore, we present model approaches for the individual components that comprise the POF-based system and how the models have been incorporated into system-level simulations, including the commercial software packages SimulinkTM and ModeSYSTM
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