The fiber optic cable world has come a long way over the past 30 years. Products have become more rugged and user friendly, making it easier for people to enter the industry and work handling optical fiber and cable. While this is great for the industry, many people may understand the “how to” but not necessarily the “why” of fiber optics. To understand the “why” behind fiber and cable products, the next step is to become a full-fledged “fiber geek.” Because the industry changes so quickly, it’s important to understand fiber specifications are continuously changing.
Bandwidth demand continues
The demand for bandwidth continues unabated, driven by Web 1.0/2.0, mobile and now streaming video. The result is an expected Compound Annual Growth Rate (CAGR) of approximately 22% across the network through 2020.
While that’s somewhat old news, new bandwidth demand is on the horizon, potentially driven by several relative sources including 4K TV, virtual reality and an expansion of the “Internet of Things.”
Ultra HD TV, also known as 4K TV, first appeared on the radar screen approximately four to five years ago. While 4K TV offers twice the resolution of standard HDTV, the first models were priced at more than $20,000. Since then, the cost of 4K TV units has dropped rapidly to the point that they are now ubiquitously available at most electronics stores.
While linear TV packages still don’t offer many 4K programming options, over-the-top video providers such as Netflix and Amazon Video are rapidly adding content.
The primary reason that 4K TV is significant to bandwidth demand is that each 4K channel requires up to 25 Mbps, more than 2X the typical HD video requirement. Considering the number of TV screens that are typically on in a household, the potential demand could be a significant increase versus current HDTV demand levels.
High resolution screens are also an integral part of the experience promised by virtual reality. Virtual reality, while in its commercialized early stages, holds the promise of significantly changing the way that we experience media of all types. However, there’s a catch – fully- networked 4K virtual reality will require hundreds of megabits per second (or more) of bandwidth(1).
High resolution video will continue to use bandwidth as it becomes embedded in various networked applications such as telemedicine, remote medical monitoring and distance learning.
Why does optical fiber care?
This bandwidth demand can be satisfied in three ways: faster electronics, more wavelengths on the fiber and more optical fiber.
Standards are important
Fiber optic standards help to ensure a minimal level of network compatibility and performance. The standards-making process is an arduous one. Fiber standards are global, and standards makers strive to achieve balance and fairness. However, standards often provide only minimum performance levels. In fact, fibers that meet the standards may struggle with some current as well as future applications.
For this reason, it’s best to insist on fiber optic performance beyond the standards for many applications.
The demand for bandwidth is expected to continue far into the future, driven in part by requirements for breakthrough applications such as higher resolution video, virtual reality and other applications. We expect this demand to continue to drive the need for optical spectrum provided by fiber. Fiber standards, such as G.652 and G.657, are very important for network designers in setting minimum performance levels but can ultimately be insufficient to meet the requirements for future networks. For this reason, performance beyond the standards can be very important.
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Reference (1): Why The Internet Pipes Will Burst When Virtual Reality Takes Off
As transmission speeds over optical fiber networks in the enterprise increase to 10 Gigabits per second (Gb/s) and beyond, a relatively new term – “laser-optimized fiber” – has crept into the industry’s vocabulary. What is laser-optimized fiber? What do you need to know about it? And what exactly does the term “laser- optimized” mean? Understanding the answers to these questions will help you prepare for the latest wave in optical communications for enterprise networks.
Why have optical fibers been “optimized” for use with lasers?
Older “legacy” optical fiber systems (Token Ring, Ethernet, FDDI, ATM) used in premises applications operated at relatively slow speeds in the range of 4 to 155 Megabits per second (Mb/s). These systems utilized inexpensive light sources called Light Emitting Diodes (LEDs), which were perfectly adequate for these slower speeds. Multimode fibers used in these systems were rated to certain minimum bandwidths, typically:
- 160 MHz/km over 62.5/125 μm fiber at 850 nm
- 500 MHz/km over 50/125 μm fiber at 850 nm
- 500 MHz/km over both products at 1300 nm
These fibers were tested for bandwidth using an Overfilled Launch (OFL) test method, which accurately replicated real-life performance with an LED.
As the demand for bandwidth and higher throughput increased, especially in building and campus backbones, LEDs could not keep pace. With a maximum modulation rate of 622 Mb/s, LEDs would not support the 1 Gb/s and greater transmission rates required. One could make use of traditional lasers (Fabry-Perot, Distributed Feedback) typically used over single-mode fiber. However these are considerably more expensive due to the higher performance characteristics required for long-distance transmission on single-mode fiber.
In response, the industry developed a new high-speed laser light source called a Vertical Cavity Surface Emitting Laser (VCSEL). These VCSELs are inexpensive and well suited for low-cost 850 nm multimode transmission systems, allowing for data rates of 1 Gb/s and 10 Gb/s in the enterprise. With the emergence of these VCSELs, multimode fiber had to be “optimized” for operation with lasers.
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What’s the Difference Between a VCSEL and an LED?
VCSELs provide higher power, narrower spectral width, smaller spot size and faster data rates than LEDs. All of these advantages add up to a significant performance boost. This assumes, of course, the fiber itself does not hinder performance. To understand why this could occur, we need to recognize the differences between VCSELs and LEDs and how they transmit signals along a multimode fiber.
All LEDs produce a smooth, uniform output that consistently fills the entire fiber core and excites the many hundreds of modes in the fiber. The bandwidth of the fiber is determined by the aggregate performance of all the modes in the fiber. If a few modes lag behind or get ahead due to modal dispersion, they have little impact on bandwidth because many other modes are carrying the bulk of the signal.
The energy output of a VCSEL is smaller and more concentrated than that of an LED. As a result, VCSELs do not excite all the modes in a multimode fiber, but rather only a restricted set of modes. The bandwidth of the fiber is dictated by this restricted set of modes, and any modes that lag or get ahead have a much greater influence on bandwidth.
Typically, a VCSEL’s power would be concentrated in the center of the fiber, where older fibers were prone to defects or variations in the refractive index profile (the critical light-guiding property in the core of the fiber), resulting in poor transmission of the signal. That is why some fibers may actually perform poorly with a VCSEL compared to an LED.
To complicate matters, the power profile of a VCSEL is nonuniform and fluctuates constantly. It changes sharply across its face, varies from VCSEL to VCSEL and changes with temperature and vibrational fluctuations. Consequently, individual VCSELs will excite different modes in a certain fiber at any given time. And because different modes carry varying amounts of power, the fiber’s bandwidth can vary in an unpredictable manner.
Why are laser-optimized fibers the best choice for use with VCSELs?
With the advent of VCSELs, it became apparent that the traditional multimode fiber deployed for LED systems did not take full advantage of the performance benefits of VCSELs.
To fully capitalize on the benefits that VCSELs offered, fiber manufacturers developed laser-optimized multimode fiber (LOMMF). LOMMF is specifically designed, fabricated and tested for efficient and reliable use with VCSELs.
LOMMFs should have a well-designed and carefully controlled refractive index profile to ensure optimum light transmission with a VCSEL. Precise control of the refractive index profile minimizes modal dispersion, also known as Differential Mode Delay (DMD). This ensures that all modes, or light paths, in the fiber arrive at the receiver at about the same time, minimizing pulse spreading and, therefore, maximizing bandwidth. A good refractive index profile is best achieved through DMD testing.
VCSELs and LOMMF provide tremendous flexibility and cost efficiency in “freeing up” bandwidth bottlenecks in the enterprise today and well into the future. LOMMF is completely compatible with LEDs and other fiber optic applications (there are no special connectors or termination required and no effect on attenuation). LOMMF can be installed now and utilized at slower data rates until the need arises to increase network speed to 1 or even 10 Gb/s. At that point, you only need to upgrade the optics modules to VCSEL-based transceivers. There is no need to pull new cable.
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Can you use any laser-optimized fiber for 10 Gb/s?
No — it is important to note that not all laser-optimized fiber is 10 Gb/s capable. If 10 Gb/s capacity is in your future, you must make sure that the LOMMF you’re installing now is capable of handling 10 Gb/s. The first laser-optimized fibers, introduced to the market in the mid-1990s, were designed for 1 Gb/s applications. Available in both 62.5/125 µm and 50/125 µm designs, these fibers extended the reach capability of 1 Gb/s systems beyond what the industry standards stated. For instance, OFS 1 Gb/s Laser Optimized 62.5 Fiber can go 300 meters in cost-effective, 1 Gb/s 850 nm (1000BASE-SX) systems. 50/125 µm fibers offer even greater performance, with a reach of 600 meters or more. These 1 Gb/s LOMMFs, coupled with 850 nm VCSELs, allow for the lowest systems cost for building backbones and short-to medium-length campus backbones
How do you measure bandwidth for laser-optimized fiber?
Since LEDs have a uniform and consistent power profile that excites all the modes in a multimode fiber, the traditional OFL method of bandwidth measurement accurately predicts bandwidth of fiber for LED applications. But because VCSELs only excite some of the modes in a fiber, and in a varying manner, the OFL bandwidth measurement cannot predict what the fiber’s bandwidth would be if the fiber were to be used in a VCSEL application.
It should become clear now why fiber manufacturers developed laser-optimized fiber, and why DMD testing is so important. The refractive index has to be well designed and controlled to ensure that all modes exhibit minimal DMD and all arrive at the other end of the fiber at the same time. No matter which modes in the fiber are actually guiding the light, those modes will have minimal DMD and provide high bandwidth.
What should you look for in DMD testing?
DMD testing provides a clear picture of how individual mode groups carry light down the fiber, and which mode groups are causing DMD. In fact, that picture is so clear that the standards require fiber to be DMD-tested to ensure adequate bandwidth to the rated distances for 10 Gb/s applications.
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Tony Irujo is sales engineer for optical fiber at OFS, a world-leading designer, manufacturer and provider of optical fiber, fiber optic cable, connectivity, fiber-to-the-subscriber (FTTx)and specialty photonics products. Tony provides technical sales and marketing support for multimode and single-mode optical fiber.
Tony has 25 years of experience in optical fiber manufacturing, testing and applications. He started with SpecTran in 1993 as a quality and process engineer and transitioned to more customer-focused roles with Lucent and OFS. He represents OFS in the Fiber Optic LAN Section (FOLS) of the TIA, has authored several papers on fiber technology and applications and is a frequent speaker at industry events. Tony has a Bachelor of Science degree in Mechanical Engineering from Western New England College in Springfield, MA.
How do you make a great fiber optic solution even better? One way is to make the optical fiber less visible while also faster and easier to install.
The new InvisiLight® Indoor Living Unit (ILU) 600 Solution from OFS is setting a new benchmark for low-profile visibility. This new solution offers fast and virtually undetectable, indoor optical fiber installation for homes, offices, and multiple living units (MDUs).
To provide Wi-Fi coverage, Fiber-to-the-Home (FTTH) and Fiber-to-the-Business (FTTB) service providers often install compact Optical Network Terminals (ONTs) deep into subscriber homes and offices. This equipment can clash with the existing décor, upsetting customers, and also create deployment issues for installers. In fact, some customers actually cancel service orders when they realize that unsightly, conventional fiber optic cables or tapes will be installed in their homes. On top of this, tight spaces, corners, architectural features, and other factors can create barriers to indoor optical fiber deployments. Fortunately, the portfolio of InvisiLight Optical Solutions was specifically designed to help meet these challenges.
Launched in 2012, the original, award-winning InvisiLight ILU Solution offers installers an innovative and simple method for indoor optical fiber installation. The process involves adhering a 0.9 mm diameter optical fiber into either crevices along ceilings and walls or moldings and walls. The result is a protected optical fiber link that is virtually invisible.
While the InvisiLight 600 ILU Solution features an even smaller 0.6 mm optical fiber, it uses the same easy installation process and tools as the original InvisiLight Solution. And, with less than half the volume and weight, the InvisiLight 80×80 Module’s storage capacity is more than doubled from 10 to 25 meters (83 feet).
All InvisiLight products, including the ILU 600 Solution, feature leading-edge OFS EZ-Bend® Optical Fiber. This fiber’s 2.5 mm minimum bend radius easily handles the sharp corners often encountered when installers conform optical fiber to a building.
In fact, in a recent field trial in Europe, an InvisiLight Solution received excellent feedback, including:
“We’re a big fan of EZ-Bend. I am amazed at some of the runs we have used it on with no apparent losses
(extreme bends, harsh pulls etc.).” – UK Service Provider
“This is the best indoor solution we have seen. Adhesive and cable are very easy to work with. Cannot
believe the low loss measured. The end customer is impressed.” – Large Ireland Network Services
Company and Ireland Service Provider
Searching for a highly-dense fiber optic cable solution with a familiar, cost-effective central core design? Then look no further than the AccuRoll™ Dry Core (DC) Rollable Ribbon (RR) Fiber Optic Cable.
The newest member of the OFS outside plant (OSP) rollable ribbon fiber optic cable line, the AccuRoll DC RR Cable offers twice the fiber density of comparable, standard flat ribbon cables in a smaller and lighter-weight cable. And, this cable is the first and only central core rollable ribbon design that features familiar linear strength elements and a protective central core tube. This core tube delivers enhanced safety for the rollable ribbons beyond that offered by other flexible ribbon cables.
What Are Rollable Ribbons? The AccuRoll DC RR Cable features rollable ribbons, the most exciting technology breakthrough in OSP cabling in years. This technology literally doubles the density of a fiber optic cable while reducing that same cable’s size and weight.
Rollable ribbons are formed by partially bonding individual 250 micron optical fibers to each other at predetermined points. These flexible ribbons can be rolled into very tight bundles for twice the density. Inside the fiber optic cable, rollable ribbons behave much like traditional ribbons, allowing highly efficient splicing using traditional flat ribbon splicing machines and procedures. The rollable ribbons can also be easily broken out into single or multiple fibers and routed.
Why the AccuRoll DC RR Cable? As fiber counts rise, but duct space and cable storage remain at a premium, smaller, lighter weight, and more flexible rollable ribbon cables are an excellent alternative to traditional flat ribbon cable technologies.
Available with 144 to 432 fibers in both metallic and dielectric designs, there’s an AccuRoll DC RR Cable to meet the needs of your application. These fiber optic cables are an excellent choice for connecting data centers or in underground, direct buried, and lashed aerial deployments.
Think about it: doubling your network’s fiber density means doubling your transmission capacity, doubling your capability, and doubling your ability to get the job done.
Fiber to the Home (FTTH) is becoming increasingly more common as bandwidth usage is exploding. This tremendous growth is driven in part by the rapid increase in Internet-connected devices and the use of data-heavy applications such as video on demand. Service providers are working to meet this need for greater bandwidth by expanding the deployment of fiber optic cables to the premises and then into the home.
Service providers building these networks all face a common challenge: the expense of the last mile in the optical network. It is critical for service providers, utilities and municipalities to have an optimized set of deployment options that help to reduce both capital and operational expenses.
The solutions presented in this article meet these challenges with several fiber deployment options from the drop point to and into the home.
OFS FTTx Solutions for the Home can help residents take advantage of the Internet of Things (IoT), which is beginning to redefine how we work and live. These solutions focus on simplicity, cost-effectiveness and speed of installation, along with the pre- and post-installation customer experience, time to revenue generation and reliable subscriber connections that help to improve profitability for the service provider.
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PRE-TERMINATED vs. FIELD-TERMINATED DROPS
Pre-terminated drop solutions are increasingly used to install fiber to homes to save time and money in higher labor cost regions. Pre-terminated drop solutions consist of drop cables that are terminated and tested in the factory, and easily plugged into the drop terminal and home terminal in the field. Pre-terminated solutions offer lower costs and faster deployment and require less installation skill.
For low labor cost markets, field terminated solutions may be preferred. Field terminated solutions use drop cables which are terminated using fusion splicing or mechanical connectors in the field during installation. They offer easier inventory management, lower material costs and easier slack management, but take longer to install and require more highly skilled labor, along with expensive field termination tools and splicing machines, when compared to pre-terminated solutions.
A third approach, with one end of the drop cable pre-terminated, and the other end field terminated, can solve the slack issue and allow an easy plug-in to the drop terminal and field termination at the home.
OFS offers all three of these drop solution options to fit the unique needs of each service provider. OFS pre-terminated solutions are available with EZ- Bend® cables that can solve the slack management challenge. EZ-Bend fiber optic cables enable the slack to be tied into a very compact bundle.
Providers typically use a combination of aerial and underground solutions to connect the last mile in a network to individual homes. A variety of factors including climate and existing infrastructure can influence solution selection.
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CONNECTING OPTICAL FIBER TO THE HOME
OFS offers a complete portfolio of aerial and underground solutions including terminals, integrated splitters and drop cables to connect to the demarcation point of individual homes. From that location, a number of solutions can be leveraged to take optical fiber into the home.
Aerial deployment is typically lower in cost and preferred where poles are in place near homes. In this scenario, a SlimBox® Drop Terminal is installed on a pole, with or without splitters, and then connected by a drop cable to as many as 16 homes. Below grade drop deployment is preferred if there is an existing duct placed from the terminal location to the home, or if below grade cabling is required by local regulations.
First, an installer inserts a feeder or distribution cable into the terminal. The installer then extracts the number of fibers required and fusion splices them to a pre-terminated splitter or drop fiber. Aerial or underground drop cables are then deployed from the terminal to individual residences.
In the case of aerial cables, a drop cable is placed between the pole and a point near a home’s roof. The cable can be connected to a demarcation box and installed into the home through the attic or onto the side of the house at a demarcation box near the ground. To help avoid unsightly aerial cables, an aerial terminal can be connected to an underground drop cable. For aerial deployments, OFS offers the one to 24-fiber Mini LT Flat Drop Cable and the single-fiber Mini TB Flat Drop cable which contains 3 mm cordage that can be routed directly to an Optical Network Terminal (ONT).
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Underground drop cable options include the single-fiber EZ-Bend® 3.0 mm and 4.8 mm Ruggedized Cables and EZ-Bend Toneable Cables. The toneable cables enable easy above ground locating of buried cables to help avoid cable cuts when other underground systems are installed. These drop cables are installed from the aerial terminal down the pole to the ground, and are then buried to minimize disruption to landscaping, or pulled into existing duct. The cable is then connected into a demarcation box installed at the side of the house, ideally in a location close to the ONT on the inside.
EZ-Bend cables are preferred since their 2.5 mm bend radius allows the cables to be coiled, bent and tied without creating signal degradation. These cables can also be buried or stapled/clipped and bent around the outer perimeter walls of a home to reach an entry point closer to the preferred ONT location.
New home construction offers a win-win situation for construction companies and service providers. With the ability to “build in” optical fiber connectivity, new homes are futureproofed from the beginning, real estate values increase, and new home owners can become immediate subscribers without the expense of additional installation time. .
Subscribers can be connected faster using preterminated cables installed to and into homes during construction. OFS offers EZ-Bend 3.0 mm and 4.8 mm cables that can be installed independently or in ducts using typical home wiring techniques, such as stapling or zip-tying of the cables, to a location or media panel where the ONT would be later placed. The home owner can later perform a “self install” by receiving an ONT from the service provider, and simply plugging in an EZ-Bend cable assembly and a power adapter to the ONT. OFS also provides a SlimBox Wall Plate that discretely blends into a home’s décor and facilitates ONT connections in the same way as a power outlet.
Existing Homes can pose a challenge to network installers, given the wide variety of possible building architectures. In addition, home designs and construction materials can vary greatly from country to country and even within countries. OFS solutions are purposefully designed and optimized to suit a variety of homes globally and offer maximum flexibility to on-site installers.
Depending on the target market, a provider can choose the terminals and drop cables for an aerial, underground or hybrid solution. The solutions described are the most popular options and feature a variety of products as building block components. This modular product design approach allows service providers to also create custom solutions to meet the specific needs of their target markets.
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Seismologists from the California Institute of Technology (Caltech) are using fiber optic network cable to monitor and record aftershocks from the July 4 and 5 Ridgecrest, CA, earthquakes. By using optical fiber, the scientists can gather, track, and analyze data in much greater depth from the thousands of daily aftershocks.
To do this, the scientists send a beam of light down optical fiber in an unused or “dark” fiber optic cable. When the light reaches tiny blemishes in the optical fiber, a small portion of the light is reflected back and recorded. In this way, each fiber imperfection acts as a trackable location along the buried fiber optic cable. When seismic waves move through the ground, the cable expands and contracts slightly. This change affects the travel time of light to and from the locations. By monitoring these changes, seismologists can monitor the motion of seismic waves.
According to Caltech, the miniscule fiber imperfections occur often enough so that every few meters of optical fiber act as an individual seismometer. In fact, monitoring 50 kilometers of fiber optic cable in three different locations is roughly equal to deploying more than 6,000 seismometers in the area.
Caltech launched the project within days of the two large earthquakes and began contacting groups in a search for unused fiber optic cable that would be close enough and long enough to be useful. The scientists finally contacted the California Broadband Cooperative’s Digital 395 project. The goal of the Digital 395 project is to build a new 583-mile fiber optic network that will run north to south, along the eastern Sierra Nevada, passing near Ridgecrest. Digital 395 offered three segments of its fiber cable to which Caltech connected sensing instruments.
Information gathered from the Ridgecrest fiber network will help seismologists learn more about the way that earthquakes move through the earth, and specifically how seismic waves move through the area around Ridgecrest.
Single Mode vs Multimode Fibers
Learn the differences and when to use single mode or multimode fibers.
Cloud computing and web services continue to drive increased bandwidth demand, pushing data communications rates from 1 and 10G to 40 and 100G and beyond in enterprise and data center networks.
These higher speeds might lead system designers to believe that single-mode optical fiber enjoys an increasing advantage over multimode optical fiber in premises applications. However, higher Ethernet speeds do not automatically mean that single-mode optical fiber is the right choice.
Although single-mode optical fiber holds advantages in terms of bandwidth and reach for longer distances, multimode optical fiber easily supports most distances required for enterprise and data center networks, at a cost significantly less than single-mode.
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Total Cost Comparison of Single Mode vs Multimode Fibers
Multimode optical fiber continues to be the more cost-effective choice over single-mode optical fiber for shorter-reach applications. While the actual cost of multimode cable is greater than that of single-mode fiber optic cable, it is the optics that dominate the total cost of a network system, dwarfing variation in cable costs.
On average, single-mode transceivers continue to cost from 1.5 to 4 – 5 times more than multimode transceivers, depending on the data rate. As faster optoelectronic technology matures and volumes increase, prices come down for both, and the cost gap between multimode and single-mode decreases. However, single-mode optics have always been more expensive than their equivalent multimode counterparts. This fact is supported by the difference in multimode vs. single-mode 10G optics, a common Ethernet speed used today.
Multimode transceivers also consume less power than single-mode transceivers, an important consideration especially when assessing the cost of powering and cooling a data center. In a large data center with thousands of links, a multimode solution can provide substantial cost savings, from both a transceiver and power/cooling perspective.
Finally, the fact that multimode optical fiber is easier to install and terminate in the field is an important consideration for enterprise environments, with their frequent moves, adds and changes.
The Difference Between Multimode and Single-Mode Fibers
The way in which these two fiber types transmit light eventually led to their separate names. Generally designed for systems of moderate to long distance (e.g., metro, access and long-haul networks), single-mode optical fibers have a small core size (< 10 µm) that permits only one mode or ray of light to be transmitted. This tiny core requires precision alignment to inject light from the transceiver into the core, significantly driving up transceiver costs.
In comparison, multimode optical ﬁbers have larger cores that guide many modes simultaneously. The larger core makes it much easier to capture light from a transceiver, allowing source costs to be controlled. Similarly, multimode connectors cost less than single-mode connectors as a result of the more stringent alignment requirements of single-mode optical fiber. Single-mode connections require greater care and skill to terminate, which is why components are often pre-terminated at the factory. On the other hand, multimode connections can be easily performed in the field, offering installation flexibility, cost savings and peace of mind.
For these reasons, multimode optical fiber systems continue to be the most cost-effective fiber choice for enterprise and data center applications up to the 500 – 600 meter range.
Beyond the reach of multimode optical fibers, it becomes necessary to use single-mode optical fiber. However, when assessing single-mode optical fibers, be sure to consider newer options. A bend-insensitive, full-spectrum single-mode optical fiber provides more transceiver options, greater bandwidth and is less sensitive to handling of the cables and patch cords than is conventional single-mode optical fiber.
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Which Multimode Fiber Type and Why?
At one time, the network designer or end user who specified multimode optical ﬁber for short reach systems had to choose from two fiber types defined by their core size, namely, 50 micron (µm) or 62.5 µm. Now, that choice is slightly different: choose from OM3, OM4, or the new OM5 grade of 50 µm multimode optical fibers. Today, 62.5 µm OM1 multimode optical fiber is virtually obsolete and is relegated for use with extensions or repairs of legacy, low bandwidth systems. In fact, 62.5 µm OM1 fiber supports only 33 meters at 10G and is not even recognized as an option for faster speeds.
50 µm multimode optical ﬁbers were ﬁrst deployed in the 1970s for both short and long reach applications. But as data rates increased, 50 µm fiber’s reach became limited with the LED light sources used at the time. To resolve this, 62.5 µm multimode optical fiber was developed and introduced in the 1980s. With its larger core, 62.5 µm optical fiber coupled more signal power than 50 µm optical fiber, allowing for longer reach (2 kms) at 10 Mb/s to support campus applications. That was the only time when 62.5 µm fiber offered an advantage over 50 µm optical fiber.
With the advent of gigabit (1 Gb/s) speeds and the introduction of the 850 nm VCSEL laser light source in the mid-1990s, we saw a shift back to 50 µm optical fiber, with its inherently higher bandwidth. Today, 50 µm laser-optimized multimode (OM3, OM4, and OM5) optical fibers offer significant bandwidth and reach advantages for short reach applications, while preserving the low system cost advantages of multimode optical fiber.
Planning for the Future
Industry standards groups including IEEE (Ethernet), INCITS (Fibre Channel), TIA, ISO/IEC and others continue to include multimode optical fiber as the short reach solution for next generation speeds. This designation reinforces multimode optical fiber’s continued economic advantage for these applications.
IEEE includes multimode optical fiber in its 40G and 100G Ethernet standards as well as its pending 50G, 200G, and 400G standards. In addition, TIA issued a new standard for the next generation of multimode optical fiber called wide band (OM5) multimode optical fiber. This new version of 50 µm optical fiber can transmit multiple wavelengths using Short Wavelength Division Multiplexing (SWDM) technology, while maintaining OM4 backward compatibility. In this way, end users can obtain greater bandwidth and higher speeds from a single fiber by simply adding wavelengths. The OFS version of this fiber is called LaserWave® WideBand Optical Fiber. This new fiber allows for continued economic benefit in deploying short reach optics using multimode optical fiber – as opposed to more expensive single-mode optics.
In general, multimode optical fiber continues to be the most cost-effective choice for enterprise and data center applications up to the 500 – 600 meter range. Beyond that, single-mode optical fiber is necessary.
>> Download the Full Article to Learn More about the Difference between Multimode or Single-Mode Optical Fibers
Already known as the state’s first gigabit city, Wilson, North Carolina, is now also that state’s first city to offer a “Fiber Optics Basics” training course at its local community college. Last month, Wilson Greenlight, the city’s community-owned, fiber-to-the-home provider, partnered with Wilson Community College to launch the pilot 10-week program.
A Long-Held Dream
The fiber optic training course is the answer to a long-held dream for Gene Scott, Wilson Greenlight’s director of outside plant. Frustrated by having highly-skilled jobs to offer that he could not fill, Scott found that standard fiber training courses cost thousands of dollars that few young people could afford.
Experts Share Knowledge/Expertise
Visiting experts from around North Carolina and the U.S. are volunteering to teach their specialty. For example, OFS expert Mark Boxer is teaching three classes covering topics ranging from the history of light wave transmission to the design of various fiber optic networks.
In one of these classes, Boxer featured a very special guest, Dr. Peter Charles Schultz. Dr. Schultz is a co-inventor of fiber optics and the recipient of the National Medal of Technology and Innovation presented by President Bill Clinton (the highest technology award of the U.S. Government). Dr. Schultz also serves as a senior advisor to and board member of OFS. During the class, Dr. Schultz described his experiences in developing fiber optics, something that few people at the time understood or valued. When asked his advice to others who might seek to blaze a new trail in the digital frontier, Schultz answered, “Be brave!”
Training for Today and Tomorrow
Other courses in the program range from how to prepare, splice and connect fiber optic cables to fiber optic safety. Instructors will expose students to various types of fiber networks, the basics on how to design a fiber-to-the-home network, how to maintain outside plant infrastructure and even how to budget and read engineering design prints.
The long-range plan is to offer a two-year partnership between a local high school and the community college. Students would leave high school with a two-year certificate in an advanced degree and qualify for higher-paying jobs after graduation. One added advantage would be to pique students’ interest in tackling a four-year college degree in new fields like fiber network management
Today the United Nations, its partners and women and girls around the world are marking the International Day of Women and Girls in Science.
Recent studies suggest that 65 per cent of children entering primary school today will have jobs that do not yet exist. While more girls are attending school than ever before, girls are significantly underrepresented in Science, Technology, Engineering and Math (STEM) subjects in many settings. They also appear to lose interest in STEM subjects as they reach adolescence. In addition, less than 30 percent of researchers worldwide are women.
As a step forward in reversing these trends, the April 2018 National Math and Science Initiative’s “Yes, She Did” campaign honored female STEM inventors. During the campaign, teachers, students, grandmothers and education enthusiasts voted fiber optic cable as the most impactful woman-influenced innovation.
One of the women highlighted in the campaign is Shirley Jackson, the first African-American woman to earn a doctorate from the Massachusetts Institute of Technology (MIT) and the first African-American woman to be awarded the National Medal of Science. She is credited with scientific research that enabled the invention of such things as the portable fax, touch-tone telephone, solar cells and fiber optic cable.
“It’s madness that women aren’t always recognized for their STEM contributions,” the National Math and Science Initiative (NMSI) wrote in introducing its social media audiences to the women behind eight highly impactful innovations. In addition to fiber optic cable, NMSI highlighted the women behind the circular saw, Laserphaco probe, dishwasher, Kevlar® Fiber, modern home security system, computer programming and NASA’s space bumper.
“Fiber optic cable shrunk the global marketplace and now everything’s connected real-time to be faster, better, stronger,” said NMSI Chief Information Officer Rick Doucette.
On this International Day of Women and Girls in Science, let’s change the trends on women in science and technology. Join us in celebrating women and girls who are leading innovation and call for actions to remove all barriers that hold them back.
The growth in Fiber to the Home (FTTH) just keeps exploding. In fact, for the first time ever, optical fiber passed DSL in home usage during 2018. Fiber is now the second most-frequent connection for North American home Internet.
And FTTH is also the second most-often-used, fixed broadband connection medium in North America. A newly-issued report from the Fiber Broadband Association (FBA) and RVA, LLC featured these statistics.
Fiber Passes xDSL
As of September 2018, the report found that all-fiber access networks surpassed xDSL connections. Almost 60 million homes were FTTH service capable and 23.8 million homes were already connected. These totals represent an increase of 22% from 2017 in terms of “homes marketed.” According to RVA, “homes marketed” depicts market potential more meaningfully than “homes passed” by fiber.
Unsurprisingly, 40.8 million of these homes are in the United States. Another 5.6 million homes are in Canada, 13.1 million in Mexico and 350,000 in the Caribbean.
In terms of the United States, new homes marketed hit a record high of 5.9 million in 2018. Of the 40.8 million homes marketed, the report calls 39.2 million “unique.” This term refers to homes that do not have more than one all-fiber operator seeking their business. Overall. FTTH connects 18.4 million homes in the U.S. Tier 1 telco operators account for 72.6% of these connections. Tier 2 and 3 operators handle 10.3%, and cable operators account for 5.5% of U.S. FTTH connections.
Canada Picks up the Pace
Canadian operators may be rolling out optical fiber faster than U.S. companies, at least in terms of homes marketed compared to total homes. However, FTTH still has a way to go to threaten hybrid fiber/coax (HFC). HFC still delivers slightly more than 50% of broadband connections in North America and FTTH provides not quite 25%.
Fiber is on Fire
According to Lisa R. Youngers, president and CEO of FBA, “The fiber industry is on fire. Fiber holds the key for next-generation connectivity, from 5G to smart cities to the Internet of Things (IOT). This research and analysis helps keep the industry, consumers and policymakers informed about FBA’s progress toward a better-connected future.”