Distributed Acoustic Sensing (DAS) is a technology that enables continuous, real-time measurements along the entire length of a fiber optic cable. Unlike traditional sensors that rely on discrete sensors measuring at pre-determined points, distributed sensing utilizes the optical fibre. The optical fiber is the sensing element.
AcoustiSens® Wideband Single-Mode Optical Fiber, the newest addition to the OFS LineaSens® family, is a vibration sensing fiber with optimal performance for DAS systems. Using a waveguide design based on the ITU-T G.657.A1 telecom-grade single-mode standard, AcoustiSens Wideband Optical Fibers significantly increase Rayleigh backscatter while maintaining low attenuation to improve Optical Signal to Noise Ratio (OSNR). Furthermore, the AcoustiSens Wideband Optical Fibers provide bend-insensitivity and expand the operating wavelength band (1536 – 1556 nm) ensuring interoperability with all known DAS interrogators.
AcoustiSens Wideband is intended for use in cables designed as sensing components in DAS systems. Without the need for changes in interrogation equipment or complex optical amplification schemes AcoustiSens Wideband is a drop-in fiber replacement that provides greatly improved sensing performance with OSNR orders of magnitude better than telecom-standard fibers. This translates into significantly improved ASNR in DAS systems. Due to its waveguide design, AcoustiSens fibers are also bend-insensitive and splice compatible with G.657.A1 and G.652.D optical fibers, assuring smooth integration with commonly deployed sensing solutions.
AcoustiSens Optical Fibers are intended for use as components in optical and hybrid cables designed for vibration or acoustic sensing applications including:
AccuCore HCF™ Optical Fiber Cable is the world’s first terrestrial hollow-core fiber (HCF) cable solution. Light travels about 50% faster in a hollow core optical fiber compared to the solid silica core of conventional fiber. Consequently, light transmitted in a hollow-core fiber arrives 1.54 microseconds faster for each kilometer traveled compared with conventional optical fiber.
The AccuCore HCF Optical Fiber Cable solution includes indoor/outdoor cable and termination with standard connectors, which are fusion-spliced to the patented photonic bandgap hollow-core fiber. OFS also offers installation services and both passive and active component selection to meet customer requirements. AccuCore HCF optical fiber cable has been successfully deployed, carrying live traffic in several networks.
This latest development from OFS was presented as a postdeadline paper on March 12, 2020 at the Optical Fiber Communication Conference and Exhibition (OFC) held in San Diego. OFC postdeadline papers represent the latest and most advanced technical achievements in the field. The paper reported error-free transmission of direct-detection 10 Gb/s DWDM signals over 3.1 km of cascaded cabled HCF. This is the first time that transmission results in a cabled HCF have been reported. That white paper is available here.
Contact OFS to learn more about AccuCore HCF fiber optic products.
The co-inventor of optical fiber, Dr. Peter Schultz, is a resident of the Virgin Islands. He was instrumental in convincing the local authorities back in the early 2000’s that the islands needed high-speed connectivity afforded by optical fiber. He assisted in the successful lobbying of federal and local governments to provide funding for the project and in 2009 The Virgin Islands Next Generation Network (ViNGN) was formed. This video shows how he partnered with OFS to deliver high-speed fiber connectivity to the U.S. Virgin Islands and specifically to his condo unit. OFS designed the fiber to the MDU (Multiple Dwelling Unit) network with the InvisiLight® Facade Solution using the 12-Fiber M-Pack® Indoor Outdoor MDU Drop Cable and SlimBox® Indoor Outdoor Enclosures. For inside the MDU, a SlimBox 64-Fiber Indoor Enclosure and the InvisiLight Indoor Living Unit (ILU) Solution were installed. OFS oversaw the installation for ViNGN with technicians from local contractor ADM Technologies, Inc.
Engineers at the California Institute of Technology have created the world’s smallest fiber optic gyroscope. Five hundred times smaller than a regular gyroscope, this new gyro can fit on a grain of rice. This research breakthrough could lead to more accurate fiber optic gyros compared to mechanical units.
WHAT OPTICAL GYROS DO
Advanced fiber optic navigation technology is critical for aircraft, missiles, unmanned aerial vehicles and ground vehicles. These machines and other platforms depend on fiber optic gyroscopes to operate safely.
HOW THEY DO THEY WORK?
A fiber optic gyroscope detects changes in position or direction using the Sagnac effect. In this way, an optical gyro functions similarly to a mechanical gyro. However, the optical gyro operates by using light passing through a coil of optical fiber.
Inside a typical optical gyroscope, a spooled-up optical fiber carries pulses of laser light. Some pulses move clockwise and others go counterclockwise. The gyro measures rotation by detecting tiny changes in how these pulses arrive at a sensor. Researchers have tried to create smaller optical gyros. However, as the size of the gyro shrinks, the signals from its sensor have grown weaker until they are drowned out by “noise” from scattered light.
WHAT THE TEAM DID
The Cal Tech research team designed a low-noise, photonic gyroscope. They etched light-guiding channels onto a two-square-millimeter silicon chip. These channels guide the light in each direction around a separate circle. This layout keeps scattered light from confusing the device’s sensors. The new design also reverses the light’s direction from time to time. This change helps to cancel out much of the related “noise.”
Optical gyroscopes that use the Sagnac effect to measure rotation could eventually be miniaturized onto nano-photonic platforms. However, thermal fluctuations, component drift and fabrication mismatch often limit the signal-to-noise ratio of these gyros. Because a microscale unit would have a weaker signal, researchers have not yet created an integrated nano-photonic fiber optic gyroscope.
Have you ever wondered how an e-mail reaches your inbox from a co-worker in Europe? Or how a Facebook message gets to you from a cousin in Africa?
The answer lies beneath the ocean. More than 745,000 miles of submarine cables featuring optical fiber make up most of the actual physical internet. These cables wind between and around continents, carrying almost all of our global internet communication.
Recently, the huge amount of data sent between connected smart devices has begun clogging this network of submarine cables, just as interstate highways become jammed with traffic. One way to deal with this massive data growth is to increase the bandwidth capacity of the physical internet. Another way is to create more direct transmission paths between continents.
Taking It Direct
A new project in Finland hopes to use this second method. The plan is to install a new fiber optic cable route across the Arctic Ocean – the only large water body that is really untouched by submarine cables. While melting sea ice raises tremendous concerns for the health of our planet, it presents an entirely new opportunity to install digital links on a straight course between continents.
For data from Asia to reach Europe, it must travel over thousands of cable miles around Asia, up through the Suez Canal and across the Mediterranean Sea into continental Europe. And while this occurs faster than the blink of an eye (about 253 milliseconds), researchers say that data and communication could travel 30 percent faster over a shorter, more direct cable route through the Arctic.
Faster Connections Are Key
Banks and financial trading groups eagerly await faster connections. Traders depend on powerful, low latency networks to buy and sell securities where milliseconds can affect profit and loss. However, big data would also benefit. Today, internet-connected devices outnumber people on the Earth by an almost 3 to 1 margin. And experts predict that internet traffic between Europe and Asia will triple in the next five years.
The deployment of this new cable would actually extend an existing cable route through Finland into Germany. And while a feasibility study by the Government of Finland calls the project a “win-win-win” for Europe, Russia and Asia, there are key areas of concern.
First, constructing this new cable route would cost nearly a billion Euros. Secondly, the icy Arctic terrain and harsh weather conditions would certainly present logistical challenges. And there are always issues involving security. However, a separate cable installation linking Tokyo and London by way of Alaska and Canada is already underway.
Our planet needs more almost supersonic connections. We can expect to see more efforts around the globe to reduce data “pile-ups” and speed the delivery of data and communication.
More fiber density in less space. From 5G to data centers to FTTx, the picture is clear. Everyone uses more bandwidth than ever before. And while bandwidth demand may seem endless, the space to install fiber optic cable isn’t. That’s why being able to install more optical fiber in the same or less space can be a game changer for today’s network operators. And it’s why “High Density” is also a critical word for many service providers today.
With microcables and rollable ribbon cables that increase fiber density while saving on space, OFS is your high-density fiber optic cable solutions provider.
Rolling In the Optical Fiber
Rollable Ribbon fiber optic cables are one of the most exciting outside plant (OSP) cabling technologies today. These cables feature rollable ribbons, the newest fiber ribbon design from OFS. This ribbon can be “rolled” (compacted) and routed like individual fibers, allowing the use of smaller closures and splice trays.
With up to 3,456 fibers, OFS AccuTube®+ Rollable Ribbon (RR) Cables help network operators double their fiber density in the same size duct or space. They also enable very efficient, cost-effective mass fusion splicing and easy individual fiber breakout. This ability helps simplify installation and save on labor costs. And by maximizing duct use, high-density AccuTube+ RR Cables are an excellent choice for connecting very large fiber distribution hubs. They are also very suitable for data centers, FTTx and access networks.
Taking Things Indoors……
With the award-winning AccuRiser™ RR and AccuFlex® RR Cables, network operators can bring the benefits of rollable ribbon cables indoors. The innovative indoor/outdoor AccuRiser RR Cable helps ease cable installation over ladder racking and through tight bends during routing. This high-density cable is excellent for use in data centers or central offices. It’s also a great choice for building-to-building cable connections along with routing for terminations and frames, and preconnectorized applications.
The strong yet flexible, plenum-rated AccuFlex RR Cable helps prevent installation problems such as packing density, routing and deployment speed. This cable’s flame rating meets NFPA 262, allowing the cable to be installed into air-handling spaces. The AccuFlex RR Cable is an outstanding solution for data centers, central offices and head ends.
And for network operators who prefer ribbon cables and the benefits of mass fusion splicing, OFS offers the AccuRibbon® DuctSaver® FX Cable. This cable makes optimal use of valuable duct space. It also maximizes the key advantages of air-blown microduct installation: rapid deployment and service turn-up.
To learn more about high-density fiber optic cables, visit our website or contact OFS at 1-800-fiberhelp.
The United States Department of Agriculture (USDA) will invest $95 million to improve or expand access to broadband internet in the rural U.S. The 12 projects involved will include converting exchanges from copper to optical fiber and also building a fiber-to-the-home network to meet future demand.
These projects will expand access to educational, social and business opportunities for rural subscribers in 11 states by connecting businesses to customers, farmers to markets and students to a world of knowledge.
Location Should Not Determine Access
According to Secretary of Agriculture Sonny Perdue, “A person’s location should not determine whether he or she has access to modern communications infrastructure. That is why the USDA is partnering with businesses and communities by investing in state-of-the-art broadband e-connectivity to remote and rural areas.”
The USDA is making the investments through the Telecommunications Infrastructure Loan Program and the Community Connect Grant Program.
Examples of the Investments
Chibardun Telephone Cooperative, Inc. in Cameron, Wisconsin, will receive a $21.4 million loan to improve outside plant facilities in four of its six exchanges. It will construct 675 miles of fiber-to-the-premises and install associated electronics. It plans to build a fiber-to-the-home network capable of sustaining customer demands in broadband connectivity for the foreseeable future.
Osage Innovative Solutions, LLC in Tulsa, Oklahoma, will receive a $2.7 million grant to construct a hybrid fiber-to-the-premises and fixed wireless system in an unserved and economically depressed portion of the Osage Nation in Osage County. The company will offer speeds up to 100 megabits per second (Mbps) download and 10 Mbps upload. This project will give customers access to high-quality telecommunications to improve economic, education and health care opportunities. Osage will provide a community center where residents can access the internet free of charge.
The Northeast Missouri Rural Telephone Company, in Green City, Missouri, is receiving a $13.7 million loan to convert six exchanges from copper plant to optical fiber to the premises. It will construct nearly 500 route miles of optical fiber.
These investments will help to improve the quality of life in rural Arizona, Iowa, Idaho, Maryland, Minnesota, Missouri, Nevada, Oklahoma, South Dakota, Wisconsin and Wyoming.
Now researchers at Ecole Polytechnique Fédérale De Lausanne (EPFL) have discovered a new method where optical fibers can identify when they are in contact with a liquid or a solid. The researchers accomplished this by generating a sound wave with help from a light beam inside the optical fiber.
A Sensor That Doesn’t Disrupt the Light
Four factors affect the light carried by a glass optical fiber: intensity, phase, polarization and wavelength. These factors can change when something stretches the fiber or the temperature varies. These changes let the fiber act as a sensor by detecting cracks in structures or temperature changes. However, until now, users could not know what was actually happening around the fiber without letting light escape, which interrupts the light path.
The method from EPFL uses a sound wave generated inside the fiber. This hyper-frequency wave regularly bounces off of the fiber’s walls. This echo varies at different locations depending on the type of material that the wave contacts. The echoes leave an imprint on the light that users can read when the beam exits the fiber. While users can study this imprint to detect and map out the fiber’s surroundings, it is so faint that it barely disturbs the light within the fiber. In fact, users could employ this technique to sense what is occurring around a fiber and send light-based information at the same time.
In experiments, the researchers submerged their fibers in water and then in alcohol, and left them out in the open air. Each time, their system correctly identified the change in the fibers’ surroundings. The group expects their technique to have many potential applications by detecting water leakage, as well as the density and salinity of fluids that touch the fiber.
Spatial and Temporal Detection
This method discerns changes in the surroundings with a time-based method. Each wave impulse is created with a slight time jag. Then, when the beam arrives, the delay is reflected. The researchers can see what any disturbances were and determine their location. The group can currently locate disturbances to within 10 meters, but have the technical means and expect to increase accuracy down to one meter.
Shades of Harry Potter’s invisibility cloak! A recent study in Optica describes a new way to achieve cloaking invisibility. In this method, researchers manipulated the frequency (color) of light waves passing through an object. This approach overcomes critical shortcomings in existing cloaking technologies. The research team says that this technique could help to secure data sent over optical fiber. It could also improve current technologies for sensing, telecommunications and information processing.
Most current cloaking devices can only conceal an object when it is illuminated with just one color of light. However, sunlight and most other light sources are broadband (i.e., they contain many colors). Also, typical cloaking solutions work by changing the dispersion path of the light around the object to be concealed.
The new solution avoids these problems by allowing light waves to pass through the object, rather than around it, while still avoiding any interaction between the light waves and the object.
To achieve this, the researchers rearranged different colors of broadband light so that the light waves passed through the object without actually “seeing” it. For example, if the object reflected green light, they would then change light in the green portion of the spectrum to another color. In this way, there would be no green light for the object to reflect. Then, once the light wave cleared the object, the cloaking device reversed the shift, returning the wave to its original state.
This spectral cloaking device could be useful in working with current telecommunication networks. These systems use broadband waves as data signals to transmit information over optical fiber. Spectral cloaking could selectively determine which operations are applied to a light wave and which are “made invisible” over certain periods of time. Service providers could use this capability to prevent eavesdroppers from gathering information by probing a fiber optic network with broadband light.
Also, providers could transmit more data over a given line by selectively removing and then reinstating colors that are used as telecommunication data signals. This capability could help to reduce “logjams” as data demands continue to explode.
Detecting ocean-floor seismic activity is crucial to our understanding of the interior structure and dynamic behavior of the Earth. However, with 70% of the planet’s surface covered by water and only a handful of permanent, ocean-bottom seismometer stations, very little overall seismic activity is actually recorded.
Now, a group of researchers from the United Kingdom, Italy and Malta have found a way to use submarine fiber optic cables already deployed on the ocean floor as seismic detectors. In a paper published in the journal Science, the research group outlines how they discovered this capability and how it would operate.
Giuseppe Marra, a member of the group, was testing an underground fiber cable between two locations in the United Kingdom. Noticing a small slowdown in signal delivery, he traced it to tiny vibrations bending the light. He then determined that the vibrations were caused by a remote earthquake. This discovery inspired him to explore using fiber optic cables as seismic detectors.