Brief introduction of Armored vs. Non-Armored Fiber Optic Cable

Fiber optic cable is offered with two different types of armor – aluminum interlocking armor for indoor cables and corrugated steel tape for outdoor cables. The armoring offers an added layer of mechanical protection to the cable. The differences between the two types of armor are the material that the armor is made of and the way it is applied to the cable. Aluminum interlocking armor is made of – you guessed it – aluminum – and it is wrapped helically around the fiber cable. This type of armor is used in indoor rated cables. The second kind of armor is corrugated steel tape. This armor is composed of coated, corrugated steel and it is folded

longitudinally around the cable. Corrugated steel tape is found in outdoor rated cables. Fiber optic cables are offered in many different cable constructions, each with their own advantages and disadvantages. Armored cables have some benefits when you are installing them, and there are applications where it will be more cost effective to use this kind of cable. Some of these cables are more versatile than others, and if you have some on hand, it may help you to be ready for any situation (like an unexpected network outage). Other times the decision will come down to the engineer and the type of cable they prefer for the job. There are costs associated that can help you make the decision about the style you choose. Armored cable costs more than non-armored, but the labor to install it may be a less expensive, and this could make it more feasible to install armored cable. Below we will discuss a few different cable constructions and where you can pick between the two, armored versus non armored.

Distribution Cable

Distribution Cable is a tight buffered cable construction; inside of the outer jacket is a layer of aramid yarn and multiple fibers with 900um tight buffer jackets. Distribution cables are multi fiber cables that are used for indoor applications. The color of the outer jacket for single mode is typically yellow and for multimode the outer jacket can be orange, aqua, magenta or lime green depending on the multimode fiber type. Having a 900um jacket on the fibers allows you to be able to terminate a connector without having to do a build up on the fiber. Where this cable is being run indoors will help to determine if armor is needed. When fiber optic cable is being run in harsh environments or high traffic areas, it would be good to have the extra protection of the armored cable. This may be in a warehouse environment or it may be above a ceiling that is accessed regularly. Indoor armored cable uses an aluminum interlocking armor that helps to protect the fiber cable, along with increasing the durability of the fiber run. Sometimes you may be required to run cable in conduit indoors. The aluminum interlocking armored cable can help eliminate the need for conduit and it can be substituted for running conduit. Installing conduit can increase the cost of the installation because you have to spend time to place the conduit. Then you have to pull the cable through the conduit which means you have essentially doubled the labor costs to perform the installation. When using the aluminum interlocking armor cable, you now just have to pull your cable once. When running the armored cable in a cable tray or under a floor or through a ladder rack – any location where it will be installed and is not likely to be touched or disturbed then you probably do not have to use armored cable.

Indoor Outdoor Cable

Another style of cable that offers an armored or non-armored construction is Indoor Outdoor Cable. This type of cable typically has a black UV resistant outer jacket as well as moisture blocking material in the Kevlar or aramid yarn of the cable. There are two different types of indoor outdoor cable that you can use. One is known as distribution style and it will have 900um tight buffer like the indoor distribution cable we talked about above. Indoor/Outdoor distribution is the same construction as the above mentioned distribution cable, except it has a special black UV rated jacket to protect the fibers inside from the sun’s rays.

Indoor Outdoor is also available as a Dry Loose Tube construction. This is where the fibers have a 250um acrylate coating only, and they are arranged in separate buffer tubes with 12 color coded bare fibers in each tube. These are similar to the next category – Outside Plant Cable, but they do not contain any water blocking gel, hence the name “Dry”. Similar to the distribution style cable, this type of cable can be armored or non-armored. The armor used in the cable is aluminum interlocking armor. This type of cable cannot be direct buried, but the armor gives the fiber some extra protection in rugged environment settings. Oftentimes installers will use this when they need to run indoors and some distance outdoors as well. Rather than needing an interconnect box at the building entrance to transition from outdoor to indoor cable, this type of cable can be run in conduit outdoors and then be brought inside without transitioning to an indoor rated cable.

This type of non-armored cable can be used in multiple applications because it is so flexible in the ways that it can be deployed. Since you can run this cable inside or outside, some contractors will purchase this type to keep on hand because they can use it for a variety of applications. This allows them the flexibility to handle multiple situations without having to carry several different spools of cable.

Outside Plant (OSP) Cable

Outside Plant Cable is a cable construction that typically has gel or Icky Pic coating the bare fibers to give it extra water blocking protection. OSP cables are run either underground or in aerial applications. These gel filled cables can only be run inside a building up to 50 feet because of the toxicity of the fumes and smoke produced when it burns. Building codes regulate this distance and the cable run will need to be inspected once it is installed. The way that this cable is installed will help to determine if you will need armor or not. Aerial and buried applications can use either armored or non-armored outdoor fiber optic cable. Here we will focus on when the cable is buried in the ground.

When you talk about outside plant cable being buried, you have a couple options as to how you can accomplish the installation. The first option has to do with non-armored cable and involves the use of conduit or innerduct. When you are running conduit underground an armored fiber is not needed but can be used if desired, because it will give the cable extra ruggedness and it will help with locating the cable later.

Armored outside plant cable is made so that it can be direct buried and it does not require the use of conduit. This type of cable construction uses corrugated steel tape for the armoring. When you bury the cable, please know how deep the frost line is in the area where you are located because the cable will need to be buried below that line. The cable is buried below the frost line so it isn’t damaged when the ground freezes and “frost heaves”. Not only is armored cable suitable for direct burial, it is also used for rodent protection. So if you have rodent trouble, it would be wise to use the armored cable. Keep in mind that the armored cable will need to be bonded and grounded for protection from lightning strikes, especially when it is used for an aerial application.

What does bonding and grounding the cable do? Basically, bonding and grounding an armored fiber optic cable protects the cable and the equipment that it connects to from electrical currents such as current from faulty or exposed wiring or lightning strikes.

Although this article does not go into the details of all applications, it does give you an idea of a few different cable constructions as well as armored versus non-armored applications. Please remember that when you are doing fiber optic cable installs, whether it is your first time or if you are a seasoned veteran, you should make sure to do your homework on the geography of the location where you will be installing, as well as mapping the path where you need to do the installation.

Advantages of Jetting Fiber Optic Cable Over Traditional Pulling

What are the advantages of blowing or jetting fiber optic cable vs. traditional pulling?

Pulling and blowing are the two primary fiber installation methods. But each of these techniques can impact the longevity, performance, and return on investment (ROI) of a fiber optic network. If you take into account the fragility of glass or fused silica during installation, distance to be covered, efficiency, and costs, you may see that jetting (blowing) offers many advantages over traditional cable-pulling techniques.

An Overview of Fiber Optic Cable Installation Methods

• Pulling: It involves pulling the fiber optic cable through pre-installed underground or aerial ducts. You can pull the cable manually or using a reeling machine. You’ll also need a pulling tape to haul the cable while measuring the distance covered.

• Blowing: With this technique, high-speed air pressure pushes fiber optic cables through standard ductwork or microduct systems.

Here are the reasons why cable jetting is superior to traditional pulling methods:

Minimal Risk of Tension Damage

Each brand of optical fiber cable has a maximum tensile strength. But in pulling, there’s a risk of straining the cable beyond its limit, which can compromise the fiber’s performance and cut its service life. Unchecked resistance forces, such as friction, on the sidewalls of cables and ducts, can also cause damage during a “pulling” installation.

In contrast, jetting involves little or no pulling, which significantly minimizes strain on the fiber optic cable. You can not only configure the system’s hydraulic pack or air-compressing equipment to control airflow inside the duct but also monitor the conduit and fiber to minimize damage.

To minimize friction during cable jetting, consider applying lubricants meant for the method. Ducts with low-friction interior walls may also help.

Suitability for Long-Haul Fiber Optic Networks

Pulling isn’t the best option for placing outside plant (OSP) fiber optic cable. With the technique, there’s always a high possibility of pulling the cable into conduit bends. And as bend angles continue to accumulate, it becomes increasingly difficult to optimize pull length. The bad news is that ducts for cross-country fiber optic networks can have many bends.

As such, pulling is ideal for short-distance fiber optic cable deployment. Distance will vary from one manufacturer to another and cable jacket material plays a role too.

With high air speed blowing fiber optic installation, however, conduit bends and undulations aren’t as much of an issue as they are with traditional cable-pulling techniques. The blowing force doesn’t pull the cable into a duct bend. It instead pushes it smoothly around every turn or curve.

In other words, the duct route geometry doesn’t impact installation distance in this case. Consequently, air-assisted installation lets you place fiber optic cable thousands of feet between jetting sites. That’s why it’s suitable for OSP fiber deployments, for example, telecommunication, CATV, and internet networks.

Reduced Costs

Cable jetting equipment and ductwork may be initially expensive. But you can amortize these upfront costs depending on current needs, and your initial investment may pay off in future savings on upgrades. For example, you don’t have to invest in redundant higher fiber counts when you can cheaply upgrade capacity in tandem with changing requirements. 

Likewise, “pulling” is more labor-intensive than the blowing method. The technique involves more equipment movement, and it may require the positioning of placing tools at intermediate points and both ends of long OSP runs. Additional workers and extra equipment translate to higher installation costs. Cable jetting requires fewer cabling technicians, however.

Keep in mind that air-assisted optical fiber installation minimizes the number of splices needed. Cables installed this way don’t usually require “figure-eight” looping to prevent twisting every time duct changes direction. Since the approach has fewer intermediate-assist placement operations, it limits the number of handholes and other access points required along the cabling route.

Suitability for Microduct Installation

Jetting is very effective in pushing fiber optic cable through microducts. With the blowing method, you can place microduct cable in continuous lengths. The technique is most suitable for modern optical fiber cables that tend to contain bare fibers, and sometimes reduced cladding diameters, both of which contribute to decreased outer cable diameters.

The thinner a fiber optic cable is, the larger the number of fibers you can place in specific innerduct. As such, jetting is the best installation technique when you wish to make the most of the available duct capacity. It also allows you to work with small but flexible fibers that go through multiple microduct twists and turns over long distances with near-zero bend losses.

Additionally, when setting up microducts for fiber optic cable jetting, you may include redundant ductwork to accommodate new fiber in the future as required. This way, you avoid the unnecessary costs of placing dark fiber, which may become obsolete sooner than anticipated.

Appropriate for Removal of Old Fiber

Pulled fiber optic cable may be difficult to remove when no longer needed. The presence of old and unwanted cables in mission-critical physical pathways may limit your ability to optimize your optical network capacity or even upgrade to higher-performance fibers.

But after installing optical fiber by cable jetting, you may easily remove it by the same approach when necessary. You may be able to reuse the removed fiber optic cable since the removal process is gentle enough to minimize or avoid damage.

Quick Installation

Cable jetting is faster than the “pulling” method. The pushing device can move fiber optic cable at speeds of 350 feet per minute or higher. With the air-jetting technique, you can quickly push cables through pre-installed innerduct or underground ductwork. But in most cases, you can only pull fiber at a rate of 100-200 feet per minute, or even slower.  

Less Disruption Choose cable jetting to upgrade your optical fiber with minimal interruption to ongoing workflows or operations. The cable-pulling approach is more disruptive.  

A Guide to Optimizing Your Fiber Optic Cable Management

How safe, efficient, and organized is your fiber optic cabling? That largely depends on your cable management practices. Optimal organization of your networking cables delivers these benefits:

• Enhanced signal integrity by minimizing macrobend losses

• Protection of cables from macro-bending damage

• Improved accessibility for maintenance and upgrades

• Quick cable identification

• Neat and aesthetically-pleasing fiber infrastructure

But you need to use the right tools and methods to optimize your fiber optic cable management. Here’s how to do it right:

Use Vertical or Horizontal Cable Managers

Vertical and horizontal cable managers hold your cabling together for orderly and efficient management. You may need them both to secure and organize your fiber-optic cables.

For example, you may place horizontal managers in front of cabinets or racks and use them to neatly hold your cables together. These tools also work well with panel patches by providing a neat way to route fiber cabling from the back to the front of the rack where switch ports are installed.

Horizontal management helps to keep cables from tangling so you can quickly make changes or identify, access, and fix specific cabling issues.

Available options include:

• D-Ring

• Finger duct

• End ring

• Brush strip

• Lacing bar

Alternatively, you may mount vertical cable managers on both sides of the rack to safely bundle your cables. This management style provides a vertical path for a large number of premise cables from switches or other network equipment.

With vertical cable management, you’re also able to separate power cords from the optical fiber cables.

Types of vertical cable management products include:

• Finger Duct Vertical Bars

• D-Ring Vertical Bars

• Vertical Lacing Bars

Use Cable Lacing Bars

Cable lacing bars provide a cost-effective way to secure and support fiber optic cabling in rack or enclosure systems. Adjustable clips or ties are used to secure cables to these metal bars. Their benefits include:

• Easing strain on cables to optimize network integrity. They also prevent strain-related damage to the ports on rack-mount devices. • Neat and aesthetically-pleasing ways to route cables horizontally and vertically. • They help with bend radius control to prevent damage to cables and minimize signal loss.

There are different shapes and types of cable lacing bars, namely:

• Round lacer bars

• Rectangular lacer bars

• L-shaped lacer bars

• Square lacer bars

• Horizontal lacer panel

• 90-degree bend lacer bar

When choosing your lacer bars, consider factors like the size of the cable runs and the offset required.

Zip Ties vs. Velcro Hook and Loop Wraps

You can also neatly and safely hold a bunch of networking cables together by wrapping or tying them. In most structured fiber optic network projects, technicians use zip ties or Velcro wraps to do that. Both options are excellent, but a look at their distinct features can help to choose the best for your cable management requirements.

Zip ties features include:

• Easy to use: Simply strap it around your cables and fasten it.

• Sturdy: They steadily secure cables in place.

• Durable: Excellent for permanent fastening.

• Cheap: Cheaply available in large quantities.

However, the main issue with zip ties is that they’re not reusable. You have to cut and get rid of them to add in more cables. Also, there is the concern that the zip tie can be “over cinched” – holding the cables together too tightly which can cause attenuation or worse – broken fibers.

Velcro straps features include:

• Reusability: To add cables to a bundle, you quickly unwrap, add, and re-wrap. Velcro straps are therefore an excellent temporary optical cabling support solution.

• Cable safety: Cutting zip ties risks damaging the cables. But unwrapping Velcro wraps involves no cutting.

Nonetheless, Velcro straps are more expensive than zip ties, although their reusability makes them a worthy investment for cable management.

Mark and Label Your Fiber Optic Cables

When you mark and label [] your fiber optic cables at both ends, you can quickly tell what you’re dealing with at all times. Doing that saves you troubleshooting time, and makes it easier and quicker to reorganize or make changes to your cabling structure. Here are some tips for getting it right:

• Size: Pick labels with sufficient space to add identification information for the size of your simplex or duplex fiber optic cables.

• Visibility: High-visibility labels display information clearly for quick identification .

• Labeling standards: Use a consistent labeling standard, such as the TIA/EIA-606-A, to name and number your optical fiber cables.

Different types of cable markers and labels include:

• ID tags: You may wrap these around bundles of cables. Other types of ID tags come with hook-and-loop closures or ties for strapping around the cables.

• Wire markers: Use these to identify individual cables. They may be numbered or color-coded to simplify the labeling process. Some are available as labeling tapes.

Cable Management With Fiber Enclosures

Fiber enclosures are boxes that house the devices and equipment that connect or terminate optic fiber cables. They’re of different types, including:

• Rack-mount enclosures

• Wall-mount enclosures

• Indoor or outdoor enclosures

The 19-inch rack-mount fiber enclosure is the most commonly deployed in fiber optic cable management and termination, and it’s usually available in five different configurations, namely 1RU, 2RU, 4RU, and 8RU. Of course, other configurations are available – these are just the most common.

Consider the following requirements to select the right rack-mount enclosure configuration:

• Number of Connections Needed: These determine the number of rack units (RU) required. A rack-mount enclosure with a larger number of RUs accommodates more fiber adapter panels. The greater the number of adapters loaded on the adapter panels, the more fibers the enclosure can hold.

• Accessibility: The type with a removable top is cheaper but more difficult to access when adding or moving cables. The slide-out or swing-out types have support trays that come out, which simplifies internal access. They cost more, however.

• Flush Mount Patch Panels: One option is the flush mount patch panel enclosure for mounting fiber optic adapters. Other rack-mount configurations may have several removable front panels. Their plug-and-play construction makes light work of fiber optic network installation and makes them an excellent cable management solution.


When your cable management is optimized, it brings organization to your cabling infrastructure, enabling you to save time, effort, and costs. This way, you can conveniently and quickly access cables within your network to implement repairs, upgrades, or other changes. Equally important, keeping your optical fiber network neat and optimally-managed means protecting it to preserve signal integrity. Still not sure of the tools or methods to use for your specific cable management solution? Contact one of our fiber optic technicians right away to explore your options!

MTP Trunks and Breakouts for 10G to 40G Migration

With the rapid development of datacom, 10Gbps is no longer enough for massive data transmission. Many data center managers set their sights on 10G to 40G migration. However, it is not possible to upgrade all 10G equipment in the cabling system because of the high cost. Therefore, finding a cost-effective solution for the migration has become a hotspot. We know that MTP cable gains great popularity among data center managers since it can provide fast installation, high density and high performance cabling for data centers. By using MTP trunk cable and MTP breakout cable respectively, there are two solutions for 10G to 40G migration. And this article is going to share these two solutions with you: MTP trunks and MTP breakouts.

Overview of MTP Trunk Cable and MTP Breakout Cable

Before we come to the migration solutions, let’s have a brief overview of MTP trunk cable and MTP breakout cable. MTP trunk cable, terminated with MTP connectors at both ends, can create the permanent fiber links between panels in a structured environment. It is typically used as backbone or horizontal cable interconnections. With efficient plug and play architecture, MTP trunk cable can greatly reduce the installation and maintenance costs. In networking applications, 12-fiber and 24-fiber MTP trunk cables are commonly used: 12-fiber MTP trunk cable is normally for 40G Ethernet network, while 24-fiber MTP trunk cable is normally for 100G Ethernet network.Here is a figure of MTO trunk cables for you.

MTP breakout cable, also named MTP fanout cable or MTP harness cable, is terminated with a male/female MTP connector on one side and several duplex LC/SC connectors on the other side, providing a transmission from multi-fiber cables to individual fibers or duplex connectors. It is typically used to connect equipment in racks to MTP terminated backbone cables. MTP breakout cable is designed for high density applications which require high performance and speedy installation without on-site termination.Here is a figure of MTP breakout cables for you.

MTP Trunks for 10G to 40G Migration

For 10G to 40G migration, you can use the MTP trunk cable. Also, MTP fiber patch panel can be used to fulfill the data transmission link. With forty-eight LC duplex adapters on the front and twelve 8-fiber MTP adapters on the rear, the high density 40G QSFP+ breakout patch panel acts as a middleman between 10G to 40G connection. The figure below shows the connectivity method. From the left to the right, four 10G SFP+ transceivers are plugged in the SFP+ interfaces on the switch on one side, then the SFP+ transceivers are connected with the front LC ports of MTP fiber patch panel by LC duplex patch cables. With the use of MTP trunk cable, the rear MTP ports of MTP fiber patch panel are linked with one 40G QSFP+ transceiver. Finally, the whole optical link is accomplished by plugging the 40G QSFP+ transceiver in the QSFP+ interface on the switch on the other side.

MTP Breakouts for 10G to 40G Migration

For 10G to 40G migration, using the MTP breakout cable is a simple way. As shown in the following picture, four 10G SFP+ transceivers are plugged in the SFP+ interfaces on the switch on one side, while one 40G QSFP+ transceiver is plugged in the QSFP+ interface on the switch on the other side. Then the MTP to LC breakout cable connects the four 10G SFP+ transceivers with the 40G QSFP+ transceiver. Finally, the data can be transmitted from 10G switch to 40G switch through the MTP to LC breakout cable smoothly.

What Are They and How to Use MTP/MPO Cables

With ever-greater bandwidths and network connections to deal with in data centers, conventional dual-fiber patch cables like LC cable can no longer meet the demands. To solve this problem, MTP/MPO cables accommodating more fibers in one multi-fiber MTP/MPO connector came into the market, which proves to be practical solutions for 40G/100G/400G high-density cabling in data centers. This article is going to introduce different MTP/MPO cable types and their applications.

MTP/MPO Cable Overview

MPO (Multi-Fiber Push-on) is the first generation of clip clamping multi-core optical fiber connector. MTP® is a registered trademark of US Conec Ltd. , which is an advanced version of MPO, with better mechanical and optical performance. They look alike and are completely compatible and intermateable. MTP/MPO cables are composed of MTP/MPO connectors and optical fibers. MTP/MPO connectors have a female type (without pins) or a male one (with pins) as shown in Figure 1. The position of guide grooves also results in “Key Up” and “Key Down” MTP/MPO connectors. And a white dot is for identifying fiber position in connectors. MTP/MPO connectors largely increase the cable density and save circuit card and rack space, which are well suited for current 40G/100G cabling and future network speed upgrades.

MTP/MPO Cable Solutions

A variety of MTP/MPO cables are available for different application environments and requirements based on functions, polarity, fiber count, fiber mode and jacket rating.

By Function

MTP/MPO trunk cables, MTP/MPO breakout cables and MTP/MPO conversion cables are ideal for high density cabling network, offering better network capacity and flexibility.

MTP/MPO Trunk Cables

MTP/MPO trunk cables are terminated with an MTP/MPO connector (female/male) on both ends, which are available in 8-144 fiber counts for users’ choices. Typically, these multi-fiber MTP/MPO trunk cables are ideal for creating a structured cabling system, including backbone and horizontal interconnections such as 40G-40G and 100G-100G direct connections, so as to achieve a simple and efficient high-performance networking.

MTP/MPO Breakout Cables

MTP/MPO breakout cables (aka. harness cables or fanout cables) are terminated with a female/male MTP/MPO connector on one end and 4/6/8/12 duplex LC/FC/SC/ST connectors on the other end, such as 8-fiber MTP/MPO to 4 LC harness cables and 12-fiber MTP/MPO to 6 LC harness cables. Typically, these breakout cables are ideal for short-range 10G-40G and 25G-100G direct connections or for connecting backbone assemblies to a rack system in the high-density backbone cabling.

MTP/MPO Conversion Cables

MTP/MPO conversion cables have the same fanout design as MTP/MPO breakout cables but are different in fiber counts and types. They are terminated with MTP/MPO connectors on both ends. Specifically, commonly-used ones are 24-fiber to 2×12-fiber, 24-fiber to 3×8-fiber, 2×12-fiber to 3×8-fiber MTP/MPO conversion cables. They are especially ideal for 10G-40G, 40G-40G, 40G-100G, 40G-120G connections, which eliminate fiber wasting and largely increase the flexibility of the existing 12-fiber and 24-fiber MTP/MPO cabling system.

By Polarity

Polarity refers to the matching of the optical transmitter and receiver at both ends of a fiber link. In traditional cabling systems, connectors like LC/ SC can be easily matched, so there is no polarity issue. However, due to the special design of MTP/MPO connectors, polarity issues must be addressed in high-density MTP/MPO cabling systems. To ensure proper polarity, the TIA 568 standard defined three connectivity methods called Method A, Method B, Method C. So there are Type A, Type B and Type C MTP/MPO cables with different structures according to these methods. These MTP/MPO cables usually connect with different MTP/MPO cassettes and fiber patch cables to ensure the right polarity of the optical circuit. Read the white paper Understanding MTP/MPO Cable Polarity for more information about common 8/12/24-fiber MTP/MPO cable polarity and connectivity methods.

By Fiber Count

8/12/24-fiber MTP/MPO cables are usually used for 40G/100G and the latest 16-fiber cables are especially designed for short-reach 400G cabling in Hyperscale data centers. 12-fiber MTP/MPO cable is the earliest developed and most commonly-used solution in 10G-40G, 40G-100G connections. But when using it to transmit 40G QSFP+ module or 100G QSFP28 module, 4 fibers will be left unused, leading to much lower fiber utilization than 8-fiber cables. While 8-fiber MTP/MPO cable system can transmit the same data rate as 12-fiber cabling with less cost and insertion loss, making it a more cost-effective solution. 24-fiber MTP/MPO cable is commonly used to establish 100GBASE-SR10 links between CFP to CFP transceivers. It allows the use of the ratified 100GBASE-SR10 20-fiber technology today, maximizing the infrastructure investment in the event of 4×25 Gb/s ratification.16-fiber MTP/MPO cables utilize the same external footprint as traditional 12-fiber MT (Mechanically Transferable) ferrule. MTP/MPO-16 solution is ideal for aggregation of multiple 8-fiber parallel transceivers and direct coupling to emerging 16-fiber parallel optic links such as 400G QSFP-DD and OSFP.

By Fiber Mode

MTP/MPO cables fall into multimode OM3/OM4 and single-mode OS2 cables. Multimode OM3/OM4 MTP/MPO cables are mostly used for short distances such as inside a building or campus, allowing maximal transmission distance of 100m (OM3) or 150m (OM4) at 40 Git/s. Single-mode OS2 MTP/MPO cables are suitable for long-reach transmission and widely deployed in carrier networks, MANs (Metropolitan Area Network) and PONs (Passive Optical Network). With less modal dispersion, the bandwidth of OS2 is higher than OM3/OM4.

By Jacket Rating

According to different fire rating requirements, MTP/MPO jackets are classified as LSZH (Low Smoke Zero Halogen), OFNP (Optical Fiber Nonconductive, Plenum), CMP (Communications Multipurpose Cable, Plenum) etc. LSZH MTP/MPO cables are free of halogenated materials (toxic and corrosive during combustion), which are ideal for confined places due to better protection for people and equipment during a fire. OFNP MTP/MPO cables contain no electrically conductive elements and are designed with the highest fire rating, which can be installed in ducts, plenums and other spaces for building airflow. CMP MTP/MPO cables can restrict flame propagation and smoke exhaust rate during a fire, which are suitable for plenum spaces, where air circulation for heating and air conditioning systems are facilitated.

Understanding Polarity in MPO System

MPO/MTP technology has led to the adoption of 40/100GbE, however on of its challenges is with regards to proper polarity of these array connections.  Maintaining the correct polarity across a fiber network enables signals from any type of active equipment to be directed to the receive port of a second piece of active equipment – and vice versa. To ensure the MPO/MTP systems work with correct polarity, the TIA 568 standard suggests several methods.

MPO Connector

First on the list is the MPO connector usually consisting of 12 fibers. 24 fibers, 36 fibers and 72 fibers Each MTP connector has a key on one of the flat side added by the body. When the key sits on the bottom, this is called key down. When the key sits on top, this is referred to as the key up position.  In this orientation, each of the fiber holes in the connector is numbered in sequence from left to right and is referred as fiber position. The orientation of this key also determines the MPO cable’s polarity.

Three Cables for Three Polarization Methods

The three methods for proper polarity defined by TIA 568 standard are named as Method A, Method B and Method C. To match these standards, three type of MPO truck cables with different structures named Type A, Type B and Type C are being used for the three different connectivity methods respectively. In this part, the three different cables will be introduced firstly and then the three connectivity methods.

MPO Trunk Cable Type A: Type A cable is also known as straight cable, is a straight through cable with a key up MPO connector on one end and a key down MPO connector on the opposite end. This makes the fibers at each end of the cable have the same fiber position.

The issue of polarity with MPO cables can be easily addressed by selecting the correct type of MPO cables, connectors, cassettes and patch cables. Various polarity settings/methods can be applied to satisfy the requirements of the 40G environment.