Understanding Fiber Optics and Local Area Networks            Products, Services and Support                              ...
Understanding Fiber Optics and Local Area Networks    Easy installation and upgrades    Optical fiber cables can be instal...
Understanding Fiber Optics and Local Area NetworksTo put these sizes into perspective, compare them to a human          Si...
Understanding Fiber Optics and Local Area Networks                                                                        ...
Understanding Fiber Optics and Local Area Networks                                                                        ...
Understanding Fiber Optics and Local Area Networks    Microbending is very localized, and the bend may not be clear-      ...
Understanding Fiber Optics and Local Area Networks                                                                        ...
Understanding Fiber Optics and Local Area Networks    Cable ratings                                                       ...
Understanding Fiber Optics and Local Area Networks               ings into riser spaces to security, surveillance or monit...
Understanding Fiber Optics and Local Area Networks                                                                        ...
Understanding Fiber Optics and Local Area Networksthe fibers. Corning Cable Systems offers several fusion splicermodels, i...
Understanding Fiber Optics and Local Area Networks        Corning Cable Systems LLC • PO Box 489 • Hickory, NC 28603-0489 ...
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Fiber and local are network understanding

  1. 1. Understanding Fiber Optics and Local Area Networks Products, Services and Support Corning Cable Systems Scalable. Robust. Cost-effective. Ready forContained In what’s now and what’s next. If this is whatThis Guide you require from your local area network, then doesn’t it make sense to demand it from the technologies supporting it? That’s• The Benefits of why optical fiber is the ideal technology for Fiber Optics local area networks. LANscape® Solutions Fiber Optic Cables ‚ Photo LAN665• Optical Fiber The Benefits of Fiber Optics In its simplest terms, fiber optics is the technology of using “waveguides” to transport information Deconstructed from one point to another in the form of light. Unlike the copper form of transmission, fiber• Inside an optics is not electrical in nature. A basic fiber optic system consists of a transmitting device, which Optical Fiber generates the light signal; an optical fiber cable, which carries the light; and a receiver, which accepts the light signal transmitted. The fiber itself is passive and does not contain any active, generative properties. (This basic information transmission sequence will be discussed in more• Optical Fiber detail later.) Parameters Optical fiber systems have many advantages over metallic-based communication systems. These advantages include:• The Basics of Fiber Optic Transmission Large bandwidth, light weight and small diameter The amount of information carried in two strands of optical fiber would require a copper cable four inches in diameter. While today’s applications require an ever-increasing amount of band-• Fiber Optic Cabling width, it is important to consider the space constraints of many end-users. The relatively small Basics diameter and light weight of optical cables make such installations in existing duct systems easy and practical, and saves valuable conduit space in these environments.• Fiber Optic Connectivity Corning Cable Systems 1
  2. 2. Understanding Fiber Optics and Local Area Networks Easy installation and upgrades Optical fiber cables can be installed with the same equipment that is used to Common Myths about install copper and coaxial cables, with some modifications due to the small size Optical Fiber and limited pull tension and bend radius of optical cables. System designers MYTH: Optical fiber is fragile. typically plan optical systems that will meet growth needs for a 15- to 20-year FACT: Fiber may be made of glass, but span. Although sometimes difficult to predict, growth can be accommodated by don’t let that fool you. Inch for inch, it’s installing spare fibers for future requirements. Installation of spare fibers today stronger than steel. Optical fiber also is is more economical than installing additional cables later. more environmentally robust than copper, and does not corrode, rust or decay when Designed for future applications needs exposed to the environment. Fiber optics is affordable today, as the price of electronics fall and optical cable MYTH: Optical fiber is so complex to pricing remains low. In many cases, fiber solutions are less costly than copper. install, it requires a specialist. As bandwidth demands increase rapidly with technological advances, fiber will FACT: Not at all. Unlike copper products, continue to play a vital role in the long-term success of telecommunications. whose designs have become increasingly complex over the years to keep up with Long distance signal transmission bandwidth demand, fiber technologies are The low signal loss and superior signal integrity found in optical systems allow trending toward ever-easier designs while much longer intervals of signal transmission without active or passive process- staying ahead of bandwidth demand. ing than metallic-based systems. MYTH: Optical fiber is cost-prohibitive. Security FACT: Actually, optical fiber is usually the Unlike metallic-based systems, the dielectric (non-conducting) nature of optical less costly investment for your network fiber makes it impossible to remotely detect the signal being transmitted within because of its nearly limitless bandwidth the cable. The only way to do so is by actually accessing the optical fiber itself. capacity and ease of upgrade. Accessing the fiber requires intervention that is easily detectable by security surveillance. These circumstances make fiber extremely attractive for security MYTH: Testing and troubleshooting is applications. difficult. FACT: Optical testing is no more difficult Non-conductivity than coaxial copper cable testing and is Optical fibers, because they are dielectric, can be installed in areas with electro- often simpler, as fewer parameters are magnetic interference (EMI), including radio frequency interference (RFI). needed to ensure the operability of optical Areas with high EMI include utility lines, power-carrying lines and railroad fiber. For example, while copper technolo- tracks. All-dielectric cables are also ideal for areas of high-lightning-strike inci- gies are affected by electromagnetic inter- dence. ference and “cross talk,” and therefore must be tested for this, fiber suffers no such Optical Fiber Deconstructed issue. Optical fiber for telecommunications consists of three components: • Core • Cladding • Coating The core is the central region of an optical fiber through which light is trans- mitted. In general, telecommunications uses sizes from 8.3 micrometers (µm) to 62.5 µm. The standard telecommunications core sizes in use today are 8.3 µm (single-mode), 50 µm (multimode) and 62.5 µm (multimode). (Single-mode and multimode will be discussed shortly.) The diameter of the cladding surrounding Core each of these cores is 125 µm. Core sizes of 85 µm and 100 µm have been used 8 µm to 62.5 µm in early applications, but are not typically used today. Cladding 125 µm Coating 250 µm Figure 1 - Cross-Section of Typical Fiber2 Corning Cable Systems
  3. 3. Understanding Fiber Optics and Local Area NetworksTo put these sizes into perspective, compare them to a human Single-mode fiber allows for only one pathway, or mode, ofhair, which is approximately 70 µm or 0.003 inch. The core light to travel within the fiber. The core size is 8.3 µm. Single-and cladding are manufactured together as a single piece of sil- mode fibers are used in applications where low-signal-loss andica glass with slightly different compositions and cannot be high-data-rates are required, such as on long spans whereseparated from one another. Contrary to myth, this glass does repeater/amplifier spacing needs to be maximized.not have a hole in the core, but is completely solid throughout. Multimode fiber allows more than one mode of light.The third section of an optical fiber is the outer protective Common multimode core sizes are 50 µm and 62.5 µm. Of thecoating which has a diameter of 250 µm. This coating is typi- two, 50 µm fiber, particularly 50 µm fiber optimized for lasercally an ultraviolet (UV) light-cured acrylate applied during the transmission, offers the highest bandwidth. Multimode fiber ismanufacturing process to provide physical and environmental better suited for shorter distance applications. Where costlyprotection for the fiber. During the installation process, this electronics are heavily concentrated, the primary cost of thecoating is stripped away from the cladding to allow proper ter- system does not lie with the cable. In such a case, multimodemination to an optical transmission system. fiber is more economical because it can be used with low-cost transmitters for high bandwidth.Types of fiberOnce light enters an optical fiber, it travels in a stable state Inside an Optical Fibercalled a mode. There can be from one to hundreds of modesdepending on the type of fiber. Each mode carries a portion of Index of refraction (IOR)the light from the input signal. Generally speaking, the num- The index of refraction (IOR) is a way of measuring the speedber of modes in a fiber is a function of the relationship of light in a material. The index of refraction is calculated bybetween core diameter, numerical aperture and wavelength, dividing the speed of light in a vacuum (the fastest possiblewhich will be discussed later. speed of light) by the speed of light in some other medium. The larger the index of refraction, the more slowly that lightEvery optical fiber falls into one of two categories: travels in that medium. • Single-mode • Multimode Total internal reflection When a light ray traveling in one material hits a different material and reflects back into the original material without any loss of light, total internal reflection occurs. Since the core Coating Coating and cladding are constructed from different compositions ofCore Core glass, theoretically, light entering the core is confined to the boundaries of the core because it reflects back whenever it hits the cladding. For total internal reflection to occur, the index of refraction of the core must be higher than that of the cladding. Cladding Cladding Light Ray Multimode Fiber Single-Mode Fiber Figure 2 - Fiber Categories Cladding CoreIt is impossible to distinguish between single-mode and multi- Figure 3 - Total Internal Reflectionmode fiber with the naked eye. There is no difference in out- Numerical aperture and the “acceptance cone”ward appearances. Only the core size is different. Both fiber Electrical signals are converted to light signals before theytypes act as a transmission medium for light, but they operate enter an optical fiber. To ensure that the signals reflect andin different ways, have different characteristics and serve differ- travel correctly through the core, the light must enter the coreent applications. through an imaginary acceptance cone. The size of this accept- ance cone is a function of the refractive index difference between the core and the cladding. Corning Cable Systems 3
  4. 4. Understanding Fiber Optics and Local Area Networks Wavelength Light that can be seen by the unaided human eye is said to be in the visible spectrum. In the visible spectrum, wavelength can be described as the color of light. To put this into perspective, take a look at Figure 5. Notice that the colors of the rainbow – red, orange, yellow, green, blue, (indigo, not shown) and violet – fall within the visible spectrum. Optical fiber transmission uses longer wavelengths Figure 4 - Acceptance Cone which are invisible to the unaided eye. (Longer wavelengths have higher readings; for example, red light has a longer wave- Light ray A: entered acceptance cone; transmitted through length than blue light.) Typical optical transmission wave- the core by total internal reflection (TIR) lengths are 850 nanometers (nm), 1300 nm and 1550 nm. Light ray B: did not enter acceptance cone; signal lost Safety note: Never look into the end of a fiber that may have a laser In simpler terms, there is a maximum angle from the fiber axis coupled to it. Laser light is invisible and can damage the eyes. at which light may enter the fiber so that it will propagate, or Viewing it directly does not cause pain. The iris of the eye will not travel, in the core of the fiber. The sine of this maximum angle close involuntarily as when viewing a bright light; consequently, seri- is the numerical aperture (NA) of the fiber. Fiber with a larger ous damage to the retina of the eye is possible. Should accidental expo- NA requires less precision to splice and work with than fiber sure to laser light be suspected, an eye examination should be with a smaller NA. Single-mode fiber has a smaller NA than arranged immediately. multimode fiber. Both lasers and light emitting diodes (LEDs) are used to trans- Optical Fiber Parameters mit light through optical fiber. (More information on lasers As with any type of transmission system, certain parameters and LEDs is available later in the text.) Lasers typically trans- affect the system’s operation. mit at 850, 1310 and 1550 nm, making them ideal for laser- optimized multimode fibers (850 nm) and single-mode fiber Increasing Frequency (1310 and 1550 nm). LEDs are used at 850 or 1300 nm, making them useful for standard multimode fiber. Window There are operational ranges of wavelengths at which the fiber best operates. Each range is known as an operating window. Each window is centered on the typical operational wave- length. Window Operating Wavelength 800-900 nm 850 nm 1250-1350 nm 1310 nm 1500-1600 nm 1550 nm These wavelengths were chosen because they best match the transmission properties of available light sources with the transmission qualities of optical fiber. Fiber Optic Applications Frequency The frequency of a system is the speed of modulation of the digital or analog output of the light source; in other words, the number of pulses per second emitted from the light source (see Figure 6). Frequency is measured in units of hertz (Hz), where 1 hertz is equal to 1 pulse or cycle per second. Longer Wavelength Figure 5 - Visible Spectrum of Light A more practical measurement for optical communications is megahertz (MHz) or millions of pulses per second.4 Corning Cable Systems
  5. 5. Understanding Fiber Optics and Local Area Networks Extrinsic attenuationA 4 pulses/second The second category of attenuation is extrinsic attenuation. (4 Hz) Extrinsic attenuation can be caused by two external mecha- nisms: macrobending or microbending. Both cause a reduction 1 second of optical power.B 7 pulses/second Macrobending (7 Hz) If a bend is imposed on an optical fiber, strain is placed on the fiber along the region that is bent. The bending strain will 1 second affect the refractive index and the critical angle of the light ray in that specific area. As a result, "B" represents a higher frequency than "A" light traveling in the core can Macrobending Figure 6 - Frequency Measurement refract out, and loss occurs. Rule of Thumb The rule of thumb for minimumIntrinsic attenuation bend radius is: A macrobend is a large-scaleAttenuation is the loss of optical power as light travels down a • 1.5-inch for bare, single-mode bend that is visible; for exam-fiber. It is measured in decibels (dB). Over a set distance, a fiber ple, a fiber wrapped around afiber with a lower attenuation will allow more power to reach • 10 times the cable’s outside person’s finger. This loss is gen-its receiver than a fiber with higher attenuation. diameter (O.D.) for non- erally reversible once bends are armored cable corrected. • 15 times the cable’s O.D. forAttenuation can be caused by several factors, but is generallyplaced in one of two categories: intrinsic or extrinsic. armored cable To prevent macrobends, all optical fiber (and optical fiber cable) has a minimum bendIntrinsic attenuation occurs due to something inside or inher- radius specification that should not be exceeded. This is aent to the fiber. It is caused by impurities in the glass during restriction on how much bend a fiber can withstand beforethe manufacturing process. As precise as manufacturing is, experiencing problems in optical performance or mechanicalthere is no way to eliminate all impurities, though technologi- reliability.cal advances have caused attenuation to decrease dramaticallysince 1970. When a light signal hits an impurity in the fiber,one of two things will occur: it will scatter or it will beabsorbed.ScatteringRayleigh scattering accounts for the majority (about 96 per-cent) of attenuation in optical fiber. Light travels in the coreand interacts with the atoms in the glass. The light waves elas-tically collide with the atoms, and light is scattered as a result.Some scattered light is reflected back toward the light source(input end). This is a property that is used in an optical timedomain reflectometer (OTDR) to test fibers. This same princi- Figure 7 - Minimum Bend Radiusple applies to analyzing loss associated with localized events inthe fiber, such as splices. MicrobendingAbsorption The second extrinsic cause of attenuation is a microbend. ThisThe second type of intrinsic attenuation in fiber is absorption. is a small-scale distortion, generally indicative of pressure onAbsorption accounts for 3-5 percent of fiber attenuation. This the fiber. Microbending may be related to temperature, tensilephenomenon causes a light signal to be absorbed by natural stress, or crushing force. Like macrobending, microbendingimpurities in the glass. Unlike scattering, absorption can be will cause a reduction of optical power in the glass.limited by controlling the amount of impurities during themanufacturing process. Corning Cable Systems 5
  6. 6. Understanding Fiber Optics and Local Area Networks Microbending is very localized, and the bend may not be clear- Modal dispersion affects multimode fibers only and is a result ly visible upon inspection. With bare fiber, microbending may of the modes of light traveling down the fiber arriving at the be reversible; in the cabling process, it may not. Microbending receiver at different times, causing a spreading effect. Graded attenuation affects all optical wavelengths. index profiles, only used in multimode fibers, are used to miti- gate the effects of modal dispersion. Bandwidth In simplest terms, bandwidth is the amount of information a fiber can carry so that every pulse is distinguished by the receiver at the end. As discussed in the previous section, dispersion causes light pulses to spread. The spreading of these light pulses causes them to merge together. At a certain distance and frequency, Figure 8 - Microbending the pulses become unreadable by the receiver. The multiple pathways of a multimode fiber cause this overlap to be much Dispersion greater than for single-mode fiber. These different paths have Dispersion is the “spreading” of a light pulse as it travels down different lengths, which cause each mode of light to arrive at a a fiber. As the pulses spread, or broaden, they tend to overlap different time. and are no longer distinguishable by the receiver as 0s and 1s. Light pulses launched close together (high data rates) that System bandwidth is measured in megahertz (MHz) at one km. spread too much (high dispersion) result in errors and loss of In general, when a system’s bandwidth is 20 MHz•km, it information. means that 20 million pulses of light per second will travel down 1 km (1000 m) of fiber, and each pulse will be distin- Input Output guishable by the receiver. Pulse Pulse The Basics of Fiber Optic Transmission As depicted in Figure 10, information (voice, data, or video) is encoded into electrical signals. At the light source, these elec- trical signals are converted into light signals. It is important to T1 T2 note that fiber has the capability to carry either analog or digi- Optical Fiber T2 > T1 tal signals. Many people believe that fiber can transmit only digital signals due to the on/off binary characteristic of the Pulse width is measured at full width-half maximum; in other words, the full width of the pulse, at half the maximum pulse light source. The intensity of the light and the frequency at height. Dispersion limits how fast, or how much, information can which the intensity changes can be used for AM and FM ana- be sent over an optical fiber. log transmission. Figure 9 - Dispersion Once the signals are converted to light, they travel down the Chromatic dispersion occurs as a result of the range of wave- fiber until they reach a detector, which changes the light sig- lengths in the light source. Light from lasers and LEDs con- nals back into electrical signals. (This is called OEO, or opti- sists of a range of wavelengths. Each of these wavelengths trav- cal-to-electrical-to-optical conversion.) The area from light els at a slightly different speed. Over distance, the varying source to detector constitutes the passive transmission subsys- wavelength speeds cause the light pulse to spread in time. This tem; i.e. that part of the system manufactured and sold by is of most importance in single-mode applications. Corning Cable Systems. Finally, the electrical signals are decoded into information in the form of voice, data or video. The index of refraction of a material is dependent on the wave- length, so each frequency component actually travels at a Inside of each of the electronics (switches, routers, etc) resides slightly different speed. As the distance increases, the pulse a receiver/photodetector to accept the incoming information becomes broader as a result. Material dispersion is a signifi- and a transmitter to send the information back out on the net- cant source of dispersion in single-mode fiber only. work. Typical switches in a local area network use an OEO6 Corning Cable Systems
  7. 7. Understanding Fiber Optics and Local Area Networks Figure 10 - Information Transmission Sequenceconversion. The data comes into the switch as an optical signal, is They offer a higher power output than VCSELs but are alsoconverted into an electrical signal and switched/routed as needed. more expensive (though less expensive than distributed feedbackThe signal is then converted back to an optical signal and sent lasers, which are also used in single-mode systems).out the port. OEO is not protocol transparent like a true opticalswitch, but does allow for the 3Rs (re-amplification, re-shape and Fiber Optic Cabling Basicsre-time) of digital signals. Cable environmentsLasers and LEDs In general, fiber optic cable can be categorized by its deploy-Historically, light emitting diode (LED) devices have been used ment environment.with multimode fiber, and are inexpensive compared to single-mode fiber lasers. The light from the LED is not very intense, Outdoor: Outside plant (OSP) cables must withstand a varietybut is sufficient to couple enough power to achieve the distances of environmental and mechanical extremes. The cable mustneeded at lower data rates. LED transmitters have been deployed offer excellent attenuation performance over a wide range offor use at 850 nm and 1300 nm, up to speeds of 622 Mb/sec. temperatures, resist water ingress, sustain years of ultravioletHowever, because LEDs cannot modulate faster than 622 radiation from direct sunlight and tolerate a wide range ofMb/sec, a new technology was developed for gigabit speeds and mechanical forces.above. Indoor: Inside plant cables generally experience a more con-Vertical cavity surface emitting lasers (VCSELs) are low-cost trolled, stable environment. Therefore, performance require-lasers that operate at 850 nm on multimode fiber to support giga- ments are based on other factors. The cables must meet thebit speeds. As a result of their higher speed capabilities,VCSELs requirements of the National Electrical Code® (NEC®) andare the optical sources utilized in transmitters for 1 gigabit and 10 local building codes based upon their installed location. Thesegigabit Ethernet multimode systems. The light emitted is more cables should also be easy to terminate.powerful and more concentrated than the light from LEDs andprovides much higher system performance. VCSELs are also sig- Indoor and outdoor: Corning Cable Systems led the develop-nificantly less expensive than typical single-mode fiber lasers and ment of flame-retardant indoor/outdoor cables. These cablesuse far less power, requiring far less cooling. use specialty materials to meet the flame-retardant require- ments of the indoor environment. They also provide reliableFabry-Perot lasers can operate in the 850, 1310 and 1550 nm waterblocking and robust construction critical for OSP use.windows and are typically used for single-mode applications. Corning Cable Systems 7
  8. 8. Understanding Fiber Optics and Local Area Networks Cable ratings Tight-buffered cables: Tight-buffered cables are designed for Article 770 of the National Electrical Code® (NEC®) requires use in building and data center backbones, horizontal applica- indoor fiber cables to meet different requirements based on tions and patch cords and equipment cables. This proven where they are placed in the environment requirement: Listed design is the most widely deployed cable type for indoor appli- most to least stringent, they are plenum, riser and general pur- cations. Tight-buffered cables contain 250 µm optical fibers pose areas. that are directly coated with a thermoplastic buffer to a diame- • Plenum area: A compartment or chamber that forms part ter of 900 µm. Tight-buffered cables are desirable for intra- FREEDM® One MIC® Cable of the air distribution system and to which one or more Indoor/Outdoor building applications because of their ability to meet building air ducts are connected. Any space with a primary function fire code requirements as MIC® as their increased physical flexi- FREEDM® One well Cable Indoor/Outdoor of air handling is also considered a plenum space. These bility, smaller bend radius and easier handling characteristics. cables must be listed OFNP or OFCP in accordance with These cables, however, are more sensitive to temperature the NEC. extremes and FREEDM® Onedisturbances than loose tube or rib- mechanical MIC® Cable Indoor/Outdoor • Riser: An opening or shaft through which cable may pass bon cables and, with the exception of Corning Cable Systems UV-Resistant, Flame-Retardant vertically from floor to floor in a building. These cables Outer Jacket FREEDM Fan-Out and FREEDM One Cables, do not have ® UV-Resistant, µm Color-Coded 900Flame-Retardant must be listed OFNR or OFCR in accordance with the 6-fiber waterblocking materials. TBII Buffered Fibers Outer Jacket NEC. Color-Coded 900 µm Water-Swellable 6-fiber TBII Buffered Fibers Strength Members • General purpose: All other indoor areas that are not plenum Water-Swellable or risers. These cables must be listed OFN or OFC in Central Strength Member UV-Resistant, Flame-Retardant Strength Members Outer Jacket accordance with the NEC. Central Strength Member Color-Coded 900 µm 6-fiber TBII® Buffered Fibers Typical cable types Water-Swellable Strength Members Loose tube cables: Loose tube cables like Corning Cable Systems ALTOS® Cables are designed primarily for OSP Central Strength Member environments and campus backbone applications. One to 12 UV-Resistant, Flame-Retardant Outer Jacket fibers are placed in individual, waterblocked buffer tubes to Color-Coded 900Flame-Retardant UV-Resistant, µm isolate them from external forces and are typically stranded TBII Buffered Fibers Outer Jacket around a fiberglass central strength member to provide addi- Color-Coded 900 µm Water-Swellable 12-fiber TBII Buffered Fibers Strength Members tional strength and resistance. A loose tube cable Water-Swellable Central Strength Member UV-Resistant, Flame-Retardant typically will hold up to 288 fibers in total within these tubes. 12-fiber Strength Members Outer Jacket With more than 25 years of successful operation in the field, Central Strength Member Color-Coded 900 µm the loose tube cable design has been used more extensively TBII Buffered Fibers than any other in the industry. It provides stable and highly Water-Swellable 12-fiber Strength Members reliable optical transmission characteristics over a wide temper- Central Strength Member ature range. Corning Cable Systems offers stranded loose tube cables for outdoor as well as indoor and indoor/outdoor riser applications. UV-Resistant, Flame-Retardant Outer Jacket Color-Coded 900Flame-Retardant UV-Resistant, µm TBII Buffered Fibers Outer Jacket Color-Coded 900 µm Water-Swellable TBII Buffered Fibers Strength Members Water-Swellable Central Strength Member 24-fiber UV-Resistant, Flame-Retardant Strength Members Outer Jacket 24-fiber Central Strength Member Color-Coded 900 µm TBII Buffered Fibers Water-Swellable PE Outer Jacket Figure 12 - FREEDM One 6-, 12- andMembers Cable ‚ Strength 24-Fiber 24-fiber Central Drawing ZA-2630 Strength Member Ripcord Dielectric Strength Members ZA-2630 (as required) Water-Swellable Tape Corning Cable Systems FREEDM Fan-Out Cables utilize ZA-2630 flame-retardant, 900 µm TBII® Buffered Fiber subunits sur- Filled Buffer Tube rounded by water-resistant, dielectric strength members and Fibers protected by a flexible, flame-retardant outer jacket. These Water-Swellable Yarn ZA-2630 Dielectric Central Member OFNR and FT-4 rated cables eliminate the need for a transi- tion splice entering the building and have 2.9 mm subunits to Figure 11 - Loose Tube Cable ‚ Drawing CPC-220/1/3 enable easy field termination. These environmentally robust, small diameter cables are ideal for routing inside/outside build-8 Corning Cable Systems
  9. 9. Understanding Fiber Optics and Local Area Networks ings into riser spaces to security, surveillance or monitoring cameras, and within telecommunications rooms and worksta- Outer Jacket tions. Dielectric Strength FREEDM® One Cable offers select attributes of both indoor Members and OSP cables. Selecting a FREEDM One Cable is often more cost effective than making a splice transition from OSP Ripcord to indoor cabling. FREEDM One Riser C is available with riser bon Cable Rib able and plenum ratings. TBII® Buffered Fiber bon Riser C Rib able Corning Cable Systems MIC® Cables, available in 2-144 fibers, are constructed by stranding the desired number of color- coded tight-buffered optical fibers around a dielectric central Flame-Retardant Figure 14 - 6-Fiber OFNP MIC Cable ‚ Drawing CPC-220/1/37 Outer Jacket member, applying a layer of strength member yarns and Ripcords horizontal array, and extrudes an acrylate coating onto and extruding a flame-retardant jacket overDielectriccable core. Corning Ribbon Riser C able the Strength Members around them. These 12-fiber ribbons can then be stacked via a Cable Systems’ unique TBII® BufferedBuffer Tube buffering method Fiber Flame-Retardant Outer Jacket cable buffering process inside a central tube. Dielectric allows for easy, one-pass stripping and Optical Fiber jacket on 2-24 a slick Ribbons Ripcords strength members are typically stranded around the tube for fiber tight-buffered cables for easierDielectric Strength pulling during cable additional durability. Members installation. Buffer Tube Optical Fiber Ribbons Flame-Retardant Outer Jacket Ribbon cables offer high fiber density in a small diameter pack- Ripcords age – a 96-fiber ribbon cable may only be half an inch in diam- Dielectric Strength Members eter. They are also ideal for mass fusion splicing or for quick BufferFlame-Retardant Tube termination with MTP® 12-fiber connectors. (See more on Outer Jacket Optical Fiber Ribbons Ripcords connectors in the next section of this guide.) Dielectric Strength Members Buffer Tube Fiber Optic Connectivity Optical Fiber Ribbons Flame-Retardant Outer Jacket One of the most important steps in the installation of fiber Ripcords Dielectric Strength optic systems is the termination of the individual fibers. There Members are several widely used termination methods. Field installing Buffer Tube the connector is commonly done using either an epoxy/polish Optical Fiber Ribbons Flame-Retardant Outer Jacket connector or the labor-saving no-epoxy, no polish connector. Ripcords Fusion splicing of pig-tails is a common practice in single- Dielectric Strength Members mode applications. Finally, a fast growing approach to termina- Buffer Tube tion is to purchase factory terminated assemblies in the form of Optical Fiber Ribbons complete pre-terminated solutions. Field installable connectors No epoxy, no polish (NENP) connectors have become a widely Flame-Retardant Outer Jacket deployed connector termination technology. As its name sug- gests, this connector type eliminates the most laborious tasks Ripcords Dielectric Strength associated with traditional connectors: the epoxy and polish of Members the fibers. These connectors utilize mechanical splicing, an Buffer Tube optical junction where two or more fibers are aligned and held in place by a self-contained assembly. In an NENP connector, Flame-Retardant Optical Fiber Ribbons the fiber to be terminated is inserted into the connector body Outer Jacket and mechanically spliced to an existing pre-polished, factory- Ripcords Figure 13 - Ribbon Riser Cable ‚ Drawing ZA-2566 installed fiber stub. ZA-2566 Dielectric Strength Members Ribbon Cables:Buffer Tubecables like Corning Cable Systems Ribbon Corning Cable Systems’ UniCam® Connectors, which are Flame-Retardant LANscape® Outer Jacket Solutions Ribbon Riser and Plenum Cables are NENP connectors, consistently exhibit excellent end-face designed primarily for indoor use, though outside and geometry characteristics, as the polishing and epoxy insertion Ripcords inside/outside versions are also available. The cable ribboniz- Dielectric Strength and adhesion are precisely measured and controlled in the fac- Members Optical Fiber Ribbons ing process takes 12 individual fibers, positions them into a Buffer Tube Corning Cable Systems 9ZA-2566
  10. 10. Understanding Fiber Optics and Local Area Networks Stripped, Cleaned and LID-SYSTEM The Most Commonly Used Cleaved Fibers are Brought Together During the Arc Unit Receiver Connector Types LID-SYSTEM® Unit Transmitter 125 125 900 900 LC Connector MT-RJ Connector Fiber Routing Guide Electrode Arcs Stage Adjust on V-Groove the X, Y, Z Planes to Align Fibers FC Connector Figure 15 - Fusion Splicing Area on the X77 Fusion Splicer ‚ Drawing ZA-703 ST® Compatible Connector termination, the UniCam Connector is the most cost-effective. SC Connector However, epoxy and polish connectors are also widely deployed as field-installable connectors. There are several ZA-703 types of connectors within this broad category, the primary dif- PUSH ference being the type of epoxy utilized to adhere the fiber TO REMOVE Pull within the ferrule of the connector (i.e., heat cure, UV cure CONEC and anaerobic). The process for terminating an epoxy and pol- MU Simplex Connector MTP® Connector ish connector includes preparing the connector and consum- ables, injecting epoxy into the ferrule of the connector, feeding tory. Unlike a traditional epoxy and polish connector, a the fiber through the ferrule micro-hole, allowing the epoxy to UniCam® Connector’s insertion loss and reflectance values are cure, scribing the fiber stub protruding from the ferrule, and much more consistent and reliable. then following a series of polishing steps. Polishing in the field is most typically performed using a hand-polishing procedure. Reflectance, in particular, is not controlled or typically meas- ured during field termination. The elimination of these Splicing pig tails processes in the field dramatically increases yield, performance A common approach to providing high quality end-face termi- ZA-2828 consistency and drastically increases ease of installation. In fact, nations is to splice a pig tail. A fiber optic pig tail is a factory- they require only a fiber-optic stripper, a cleave tool, the work- finished connector with a pre-determined length of fiber station installation tool and an alcohol pad. As a result, assem- attached. This length of fiber can be spliced, typically via bly space can be kept to a minimum, setup is quick and assem- fusion splice; however, it can be mechanically spliced to anoth- bly is relatively fast and easy with no consumables. When tak- er segment of cable to complete the cable run. The factory- or ing into account the material, labor and consumables costs of machine-finished connector enables the installer to provide a connector type that may be difficult to achieve using a field installable connector, such as an APC connector. Pig tail splic- ing requires a splice tray and housing to ensure these connec- tions are well protected from physical or mechanical factors. Fusion splicing Fusion splicing consists of aligning and then fusing together two stripped, cleaned and cleaved fibers with an electric arc. The fiber ends can be positioned and aligned using various methods, and can be manual or automatic. This is typically accomplished with the aid of a viewing scope, video camera or a specialized type of optical power meter. High voltage applied UniCam SC Multimode Connectors ‚ Photo LAN685 to the electrodes contained in the splicer generates an arc across the fiber ends as the fibers are moved together, fusing10 Corning Cable Systems
  11. 11. Understanding Fiber Optics and Local Area Networksthe fibers. Corning Cable Systems offers several fusion splicermodels, including the Model X77 and X75 Micro FusionSplicers for fast, reliable fusion splicing at an economical price.Preterminated solutionsA value-adding innovation for the security market is the use ofpreterminated solutions in the indoor and outside plant environ-ment. This solution eliminates field termination, and thereforeenables deployment at speeds several times faster than traditionalfield installation methods. The traditional installation of fiber ter-minals and closures, particularly in an outside plant environment,is a time-consuming and costly task. Minimizing these issues,coupled with the quality and reliability of a factory-terminated- Plug & Play OSP System ‚ Photo LAN725and-tested system, maximizes the probability of rapid, cost effec-tive, flexible and high-performance installations. Corning Cable Systems’ Plug & Play™ OSP Systems utilizes stan- dard optical fiber cables upon which network access points are pre-installed at customer-specified locations along the length of the cable. The cable and network access points are tested and shipped as a complete distribution cable/terminal system. Plug & Play OSP Systems can be deployed aerially or below ground in the outside plant. Optical hardware: Optical hardware is another key component in the complete opti- cal cable infrastructure, as it provides optical connection manage- ment, protection of optical connections, labeling of optical cir- Plug & Play Universal Systems ‚ Photo LAN656 cuits, consolidation points for multiple cable runs, and security of optical connections.Plug & Play™ Universal Systems is a preterminated cabling sys-tem for indoor applications. Preterminated cable trunks with a Optical hardware selection is typically based on environment,factory-installed protective pulling grip are routed through volume of connections and type of connections. There are manythe cabling pathways and spaces. Once deployed, the pulling grip hardware options to choose from when designing a security net-is removed and the exposed connectors on both ends of the work. Typical options include splice closures, pedestals, cabinetstrunks are plugged into patch panels or system equipment. and housings; hardware that is rack- and wall-mountable, out-Because the trunks use high-density MTP® Connectors on the door weather-proof, industrial-grade, aerial, below-ground, directends, they plug quickly and easily into modules or harnesses for buried, high-fiber-count, low-fiber-count and secure/lockablesimple, fast, modular solutions that are easily scalable. products, just to name a few. Corning Cable Systems 11
  12. 12. Understanding Fiber Optics and Local Area Networks Corning Cable Systems LLC • PO Box 489 • Hickory, NC 28603-0489 USA 800-743-2675 • FAX: 828-901-5973 • International: +1-828-901-5000 • www.corning.com/cablesystems Corning Cable Systems reserves the right to improve, enhance and modify the features and specifications of Corning Cable Systems products without prior notification. ALTOS, FREEDM, LANscape, MIC and UniCam are registered trademarks of Corning Cable Systems Brands, Inc. Plug & Play and Pretium are trademarks of Corning Cable Systems Brands, Inc. MTP is a registered trademark of USConec Ltd. Discovering Beyond Imagination is a trademark of Corning Incorporated. ST is a registered trademark of Lucent Technologies. All other trademarks are the properties of their respective owners. Corning Cable Systems is ISO 9001 certified. © 2006 Corning Cable Systems. All rights reserved. Published in the USA. LAN-737-EN / May 2006 / 10M