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Comparison Between Different Fiber Optic Cable Types

Nowadays more and more fiber-based networks have been built in the backbone and risers environment. Both multimode and single-mode fibers are available for the applications. But different fiber types have briefly different limitations for speed and maximum distance. These characteristics they possess and the way cause the fiber to operate determine the application to which a given fiber is most appropriate. Today’s article will offer you some information about the classification of fiber optic cables and the difference in speed and distances.

Difference Between OM Multimode Fibers

Multimode fibers, according to the specification and briefly by their bandwidth performance are commonly classified into OM1, OM2, OM3 and OM4. Each multimode type has different transmission data rates, link length and bandwidth for specific protocols, applications and transceiver types. Table 1 outlines the international standards organization classification for multimode fiber which describe the strength for speed and distance.

multimode-fiber

From the above table, we can see that OM1 is the 62.5-micron fiber, while OM2/OM3/OM4 are the 50-micron multimode fibers. OM1 multimode fiber was used to be the most common multimode fibers in the 80’s and 90’s. However, it is generated accepted that OM1 will soon be obsolete for the lowest data carrying capacity and shortest distance limitations as compared with other multimode fibers. As for the 50-micron multimode fibers, they are the most commonly used fiber types today, especially the OM3 and OM4 cables. Why do the multimode fibers with a smaller diameter have better performance than the large one? Please read on.

In terms of the performance in 50-micron and 62.5-micron multimode fibers, the difference lies in the fibers’ bandwidth, or the signal-carrying capacity. Bandwidth is actually specified as a bandwidth-distance product with units of MHz-km that depends on the data rate. As the data rate goes up (MHz), the distance that rate can be transmitted (km) goes down. Thus, a higher fiber bandwidth can enable you to transmit at higher data rates or for longer distances. For example, 50-micron multimode fiber offers nearly three times more bandwidth (500 MHz-km) than FDDI-grade 62.5-micron fiber (160 MHz-km) at 850 nm.

While fiber bandwidth is a critical factor in determining link length and data rate, transmitter and receiver characteristics also matters. For 850-nm Gigabit Ethernet, these bandwidth values support link lengths of 220 meters over 62.5-micron fiber and 550 meters over 50-micron fiber. For example, Cisco GLC-SX-MM operating at 850-nm can support a link distance of 550 m over 50-micron fiber (OM2). Today, the 850-nm operating window is increasingly important, as low-cost 850-nm lasers such as verti cal-cavity surface-emitting lasers (VCSELs) are becoming widely available for network applications. VCSELs offer users the ability to extend data rates at a lower cost than long-wavelength lasers. Since 50-micron multimode fiber has higher bandwidth in the 850-nm window, it can support longer distances using these lower-cost VCSELs. Thus, 50-micron multimode fiber is more suitable for fiber backbones running Gigabit Ethernet and higher-speed protocols over longer distances.

Multimode vs. Single-mode Fibers

Single-mode fiber, owing to the more expensive electronics required in the network, is usually used for much greater-reach applications but not a cost-effective investment for future application in building. As the multimode fibers can be divided into OM1, OM2, OM3 and OM4 fiber types, single-mode fibers usually come in OS1 and OS2 fibers. For the detailed information, please look at the article “The Truth About OS1 and OS2 Optical Fiber”.

Jacket color is sometimes a simple method to distinguish multimode cables from single-mode ones. The standard TIA-598C recommends, for non-military applications, the use of a yellow jacket for single-mode fiber, and orange or aqua for multimode fiber, depending on type as you can seen in the Figure 2.

fiber-optic-cable

Besides the jacket color, the difference between multimode and single-mode optical fiber (9-mircon core) is that the former has much larger core diameter; much larger than the wavelength of the light carried in it. Because of the large core and the possibility of large numerical aperture, multimode fiber has higher “light-gathering” capacity than single-mode fiber. In practical terms, the larger core size simplifies connections and also allows the use of lower-cost electronics such as light-emitting diodes (LEDs) and vertical-cavity surface-emitting lasers (VCSELs) which operate at the 850 nm and 1300 nm wavelength (single-mode fibers used in telecommunications typically operate at 1310 or 1550 nm). However, compared to single-mode fibers, the bandwidth & distance product limit of multimode fiber is lower. Because multimode fiber has a larger core-size than single-mode fiber, it supports more than one propagation mode; hence it is limited by modal dispersion, while single mode is not.

fiber-cable-type

The light sources used in these two cable types also plays a critical role in the performances. The LED light source sometimes used with multimode fiber produce a range of wavelengths and these each propagate at different speeds. This chromatic dispersion is another limit to the useful length for multimode fiber optic cable. In contrast, the lasers used to drive single-mode fibers produce coherent light of a single wavelength. Due to the modal dispersion, multimode fiber has higher pulse spreading rates than single mode fiber, limiting multimode fiber’s information transmission capacity. Thus, single-mode fibers are often used in high-precision scientific research because restricting the light to only one propagation mode allows it to be focused to an intense, diffraction-limited spot.

Conclusion

The growth in subscribers’ demand for more sophisticated electronics and web-connected services increases the requirement for information storage and cloud technology. End-users also want to know how to choose the right cable type for your network application. Therefore , I hope after reading this article you might have learned something from it.

How to Choose Between Coaxial Cable, Twisted Pair and Fiber Optic Cables?

As enterprises are striving for high reliability and performance as well as seamless data access and reporting, industrial networks are becoming more sophisticated. In terms of cabling solutions, it is essential to use the industrial Ethernet cable to achieve reliable performance. However, with so many fiber optics for sale, to select a right cable for broadband connection services is challenging. Coaxial cables and twisted pair or fiber optic cables are available for network connectivity. So which one is an ideal choice, coaxial cable or twisted pair cable? Is the fiber optic cable that fits your needs most? This article outlines the coaxial cable, twisted cable and fiber optic cables to help you select the right cable for your network.

Describing Coaxial Cable

Coaxial cable, or coax cable, is a single wire usually copper wrapped in a foam insulation. Because of its insulating property, coaxial cable can carry analogy signals with a wide range of frequencies. Thus it is widely used in feedlines connecting radio transmitters and receivers with their antennas, computer network connections, digital audio (S/PDIF), and distributing cable television signals. Over time, the industry settled on two characteristic coaxial cable impedances for the vast majority of applications: 50 Ohm and 75 Ohm.

coaxial_cable

The above figure shows the internal structure of the coaxial cables. In the middle of the coaxial cable is what is known as the center conductor. It can be made of either solid or stranded wire and is typically a mix of Aluminum and Copper. Surrounding the center conductor is something called the dielectric. The dielectric acts as a buffer of sorts to keep the center conductor isolated and straight. It usually is comprised of some blend of plastic and/or foam. Finally, on the outside of the dielectric is the coaxial cable’s shield, which is usually a combination of Copper and Aluminum foil and/or wire braid. The shield is then coated by something like PVC to insulate it from the environment.

Twisted Pair Cable Overview

Twisted pair cable is a type of copper wiring in which two conductors of a single circuit are twisted together. The twisting feature can avoid noise from outside sources and crosstalk on multi-pair cables, so this cable is best suited for carrying signals. Generally it comes in two versions: Shielded Twisted Pair (STP) and Unshielded Twisted Pair (UTP). STP is commonly used in Token Ring networks and UTP in Ethernet networks. Besides STP and UTP cables, twisted pair cables can be alao found in Categories cable. For instance, Cat 6 twisted pair cables are used for 1000BASE-T and 10GBASE-T networks. The image below displays the STP and UTP cables.

stp-utp-cable

Finally Comes to Fiber Optic Cable

A fiber optic cable is a cable containing one or more optical fibers. Fiber optic cables often contain several silica cores, and each fiber can accommodate many wavelengths (or channels), allowing fiber to meet ever-increasing data capacity requirements. When terminated with LC/SC/ST/FC/MTRJ/MU/SMA connectors on both ends, fiber optic cables can achieve fiber link connection between equipment during fiber cabling. Nowadays, two types of fiber optic cables are widely adopted in the field of data transfer—single mode fiber optic cables and multimode fiber optic cables. Take LC to ST fiber cable for example, the LC to ST 10G OM4 multimode fiber cable (seen in the below image) is utilized for 10G short-reach applications, while the LC to ST single-mode fiber cable can be used for long-reach application.

lc-to-st-om4-fiber-cable

Comparison Between These Cables

When considering which kind of fiber cable is appropriate for network services, one thing you should keep in mind that each type of cable has its unique advantages and disadvantages concerning about these factors—cost, speed, security, reliability, bandwidth, data carrying-capacity, and so on.

Coaxial Cable can be installed easily, relatively resistant to interference. However, it is bulky and just ideal for short length because of its high attenuation. It would be expensive over long-distance data transmission. While Twisted Pair Cable is most flexible and cheapest among three kinds of cables, easy to install and operate. But it also encounters attenuation problem and offers relatively low bandwidth. In addition, it is susceptible to interference and noises.

As for fiber optic cables, it is treated as the most popular mediums for both new cabling installations and upgrades, including backbone, horizontal, and even desktop applications. Compared with the other two cables, fiber optic cable is small in size and light in weight, and the conductor is glass which means that no electricity can flow through. In addition, fiber cable is immune to electromagnetic interference. The biggest advantage of fiber optic cable is that it can transmit a big amount of data with low loss at high speeds over long distance. Nevertheless, it needs complicated installing skills, difficult to work with and expensive in the short run.

Conclusion

With all the features and disadvantages of the cables listed above, it is time for for you to make your won choice. Note that the cost of the cable is compared to the high costs of network failure, which can be thousands of dollars per minute. Therefore it is make sense to choose and install the right cable for your LAN network. FS.COM provides a full range of fiber optics including the cables, optical transceivers, patch panels, and fiber enclosures, etc. Other cables such as Cat 5e, Cat 6, Cat 6A are also available for your copper networks. Welcome to visit FS.COM for more detailed information.

Difference Between Twisted Pair Cable and Coaxial Cable

A wire or cable is an indispensable element in communication system for connecting optical devices like optical transceivers, router and switch. Recently the most common cable types deployed in communication system are fiber optic cable, twisted pair cable and coaxial cable. Both twisted pair cable and coaxial cable are copper cables, so what’s the difference between them? This article may help you sort it out.

Twisted Pair

Twisted pair cables as the names implies, consists of a pair of cables twisted together, which has been utilized in telecommunication field for a long time. The twisting can avoid noise from outside sources and crosstalk on multi-pair cables, so this cable is best suited for carrying signals. Basically, twisted pair cable can be divided into two types: unshielded twisted-pair (UTP) and shielded twisted-pair (STP).

twisted-pair

UTP is for UNshielded, twisted pair, while STP is for shielded, twisted pair. UTP is what’s typically installed by phone companies and data communication (though this is often not of high enough quality for high-speed network use) and is what 10BaseT Ethernet runs over. However, STP distinguishes itself from UTP in that it consists of a foil jacket which helps to prevent crosstalk and noise from outside source. It is typically used to eliminate inductive and capacitive coupling, so it can be applied between equipment, racks and buildings.

Coaxial Cables

Coaxial cable is composed of an inner solid conductor surrounded by a paralleled outer foil conductor that is protected by an insulating layer. A coaxial cable has over 80 times the transmission capability of the twisted-pair. Coaxial cable has also been the mainstay of high speed communication and has also been applied to network with 10 Gigabit links data centers, because it is proved to be cost efficient for short links within 10 m and for residential network.

coax cable

Comparison Between Twisted Cable and Coaxial Cable

Most people now are quite familiar with what coaxial cables are, as they are used in almost every home for cable television connections. These data cables are also popular in local area networks (LAN) because they are highly resistant to signal interference, which also gives coax cables the ability to support longer cable lengths between two devices.

The biggest advantage of twisted cables is in installation, as it is often thinner than coaxial cables and two conductors are twisted together. However, because they are thinner, they can not support very long runs. These tightly twisted designs cost less than coaxial cables and provide high data transmission rates. They connect with the RJ45 connector, which looks similar to a telephone jack but is designed for twisted pair pins.

In the end, twisted pair cabling is better suited when cost and installation are an issue and if EMI and crosstalk are not too much of a problem. But for coaxial cable, it supports greater cable lengths, and can be shielded in a variety of ways—with a foil shield on each conductor, a foil or braid inside the jacket or a combination of individual conductor and jacket shielding.

Additional Information About Fiber Optic Cables

Besides Twisted and coaxial cables, here comes a new generation of transmission media—fiber jumper. Fiber optic cables have a much greater bandwidth than metal cables, which means they can carry more data. They are also less susceptible to interference. For these two reasons, fiber optic cables are increasingly being used instead of traditional copper cables despite that they are expensive. Nowadays, two types of fiber optic cables are widely adopted in the field of data transfer—single mode fiber optic cables and multimode fiber optic cables.

LC-SC fiber patch cable

Single mode optical fiber is generally adapted to high speed, long-distance applications. While a multimode optical fiber is designed to carry multiple light rays, or modes at the same time, which is mostly used for communication over short distances. Optical fiber cables are also available in various optical connectors, such as LC to SC patch cord, LC to ST fiber cable, SC FC patch cord, etc. The picture above shows a LC to SC patch cord.

Conclusion

Some engineers confirm that fiber optic cables is sure to be the dominant transmission media in telecommunication field, while others hold that copper cables will not be out of the stage. Thus, whether to choose fiber optic cables, twisted cables or coaxial cables, it is advisable for you to have a full understanding of your application before selecting these data cables. All types of Ethernet cables as well as fiber optic cables are provided at FS.COM. Our Quick Order Tool will help you find what you need. If you have any requirement of our products, please send your request to us.

A Quick Lesson in Fiber Optics

Fiber optics, with its high bandwidth capacities and low attenuation characteristics, is considered to be the ideal building equipment in the telecommunication field. Depending on the type of application and the reach to be achieved, various types of optical fiber may be considered and deployed. This article is devoted to provide solutions to the questions about fiber optic cables. After going through the whole passage, you might form a basic understanding of optical cables.

What Is an Optical Fiber?

Core and cladding are the two main elements of an optical fiber. The core as shown in the image below, is the axial part of the optical fiber made of silica glass, which is the light transmission area of the fiber. The cladding is the layer completely surrounding the core. The refractive index of the core is higher than that of the cladding, so that light in the core strikes the interface with the cladding at a bouncing angle, gets trapped in the core by total internal reflection, and keeps traveling in the proper direction down the length of the fiber to its destination.

internal structure of fiber optics

There is usually another layer, called a coating surrounding the cladding that typically consists of protective polymer layers applied during the fiber drawing process, before the fiber contacts any surface. As we all known, the most typical types of fiber optic cable are MM fiber patch cords and single mode fiber optic cables.

How Do Fiber Optics Work?

Fiber optics use light pulses to transmit signals from one end to another. Light passes through the optical cable, bouncing off the cladding until it reaches the other end of the fiber channel, which is called total internal reflection. The diameter of the core corresponds directly with the angle of reflection.

As this diameter increases, the light requires more reflections and a greater amount of time to travel a given distance. For example, single mode fiber optic cable has a smaller diameter core which makes itself suitable for long distance, higher bandwidth runs. Multimode fiber, however, has a larger diameter core and is more commonly used in shorter cable runs.

What You Need to Know About Optical Fiber?

Attenuation and Wavelength

Light is gradually attenuated when it is propagated along the fiber. The attenuation value is expressed in dB/km. It is a function of the wavelength (λ), meaning that the operating wavelength to transmit a signal in an optical fiber is not any wavelength. It corresponds to a minimum of attenuation.

The typical operating wavelengths that light sources have been developed for are 850 nm and 1300 nm in multimode, and 1310 nm and 1550 nm in single mode. For a 850 nm operating wavelength, there is a 3dB light attenuation after 1 km propagation. 3 dB means that half of the light has been lost.

Bandwidth

Bandwidth is a measure of the data-carrying capacity of an optical fiber. For example, a fiber with a bandwidth of 500 MHz.km (Mega-hertz kilometer) can transmit data at a rate of 500 MHz along one kilometer. Bandwidth in single mode fibers is much higher than in multimode fibers.

How to Link Two Optical Fibers?

Fusion Splice

This operation usually needs a fusion splicer to accomplish the process. In this method, optical technician directly links two fibers together by welding with an electric arc, by aligning best possible both fiber cores. Compared with other method, this linking method is fast and relatively simple to make. And the light loss generated by the welding, due to an imperfect alignment of the cores, remains very weak.

However, just as the coin has two sides, this link method has drawbacks. In spite of a protection of fusion by a heat-shrinkable tube, this type of link is relatively fragile. It is a permanent link. What’s worst, the fusion splicer is usually very expensive.

Use of Connectors

In this case, it is necessary to terminate a connector at each end of the fibers to be connected. The two fibers can then be connected by connecting the two connectors together. The following picture shows a SC fiber patch cord.

SC fiber patch cord

Just as the following picture shows, this type of connection is robust. The type of connector can be chosen according to the application field of the system. Unlike fusion splice, this connection is removable. It is possible to connect and disconnect two fibers hundreds to thousands times without damaging the connectors. But the implementation is longer than fusion, and requires an experiment as well as specific tools. Furthermore, the light loss due to connection is higher than in the splicing solution.

Why to Choose Fiber Optics?

The main advantages of fiber optics are the followings:

  • Lower loss: Optical fiber has lower attenuation than copper conductors, allowing longer cable runs and fewer repeaters.
  • Increased bandwidth: The high signal bandwidth of optical fiber provides a significantly greater information-carrying capacity. Typical bandwidths for multimode fibers are between 200 and 600 MHz.km, and > 10 GHz.km for singlemode fibers. Typical values for electrical conductors are 10 to 25 MHz.km.
  • Immunity to interference: Optical fibers are immune to electromagnetic and radio frequency interference and also emit no radiation themselves.
  • No detection: Standard fiber optic cables are dielectric, so they cannot be detected by any type of detector.
  • Electrical isolation: Fiber optics allows to transmit information between two points at two different electrical potentials, and also next to high voltage equipments.
  • Decreased size and weight: Compared to copper conductors of equivalent signal-carrying capacity, fiber optic cables are easier to install, require less duct space, and weight about 10 to 15 times less.

Conclusion

The Internet nowadays is largely based around optical fiber. For those who do not understand fiber optics, they will have confusion and misconceptions when working with fiber optic networks. This article probably will not make you an optical engineer, but it will guide you to touch on a little bit of every topics, from the theoretical to the practical even if you aren’t designing optical networks. FS.COM offers s variety of fiber optic cables with the highest quality and low price. If you are interested, you can contact us.

What Will Affect the Longevity of Your Fiber Network?

When deploying a fiber network, people nowadays not only appreciate the high-speed broadband services, but the maintenance of how long it will last. After all, optical fiber is a particular type of hair-thin glass with a typical tensile strength that is less than half that of copper. Even though the fiber looks fragile and brittle, but if correctly processed, tested and used, it has proven to be immensely durable. With this in mind, there are essentially factors that will affect the longevity of your fiber network.

fiber network

Installation Strains

Stress, on the other hand, is a major enemy of fiber longevity, so the protection task is passed to the cable installer, who will ensure that the use of suitable strength elements limits the stress applied to the cable to much less than the 1 per cent proof test level. The installer then needs to ensure that the deployment process does not overstrain the cable. Figure 2 below illustrates a typical crew deployment for a trunk installation. The whole process should be paid more attention to the stress.

Figure 2 below illustrates a typical crew deployment for a trunk installation

Of the three techniques commonly used—pulling, pushing and blowing, only pulling creates undesirable stretching (tensile stress). Unlike metal, glass does not suffer fatigue by being compressed, and so the mild compression caused during pushing causes no harm to the fiber.

Surface Flaws

Optical fiber typically consists of a silica-based core and cladding surrounded by one or two layers of polymeric material (see in Figure 3). Pristine silica glass that is free of defects is immensely resistant to degradation. However, all commercially produced optical fibers have surface flaws (small micro-cracks) that reduce the material’s longevity under certain conditions. The distribution of flaws on the surface of the silica-based portion of the fiber largely controls the mechanical strength of the fiber. FS.COM fiber optic cables are well tested to ensure less surface flaws, like LC to ST fiber cable.

standard opticla fiber

To conquer this, reputable fiber suppliers carry out proof testing, which stretches the fiber to a pre-set level (normally 1 per cent) for a specified duration to deliberately break the larger flaws. And the user is then left with a fiber containing fewer, smaller flaws that need to be protected from unnecessary degradation. This means primarily stopping the creation of new flaws by coating the fiber with a protective and durable material for its primary coating.

Environmental Factors

Once deployed, the local environment has a big impact on fiber life. Elevated temperatures can accelerate crack growth, but it is the presence of water that has been historically of most concern. The growth of cracks under stress is facilitated by water leading to “stress corrosion”. You can check what the tendency of a fiber to suffer stress corrosion is by reviewing its “stress corrosion susceptibility parameter”, much more conveniently referred to as “n”. A high n value (around 20) suggests a durable fiber and coating.

Calculating How Long Your Network Will Last

Bearing in mind the three factors above, how can you calculate the lifetime of your fiber network? In general, the chances of a fiber being damaged by manual intervention, such as digging, over the same time frame is about 1 in 1,000. Quality fiber, installed by benign techniques and by careful installers in acceptable conditions should, therefore, be extremely reliable – provided it is not disturbed.

It is also worth pointing out that cable lengths themselves have rarely failed intrinsically, but there have been failures at joints where the cable and joint type are not well matched, allowing the fibers to move – for example, due to temperature changes. This leads to over stress of the fiber and eventual fracture.

Conclusion

To tell the truth, the biggest enemies to the carefully engineered reliability of fiber jumper can be either humans or animals, rather than the fused silica itself. The provided fibers are stored and coiled correctly, it is quite possible that they turn out to be stronger than we at first thought and perhaps the original flaws begin to heal with time and exposure to water under low stress levels. FS.COM offers high quality fiber cable assemblies such as Patch Cords, Pigtails, MCPs, Breakout Cables etc. All of our products are well tested before shipment. If you are interested, you can have a look at it.