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When we talk about multimode fiber optic cables we are typically refering to either 50/125μm fiber or 62.5/125μm fiber. The 50μm and 62.5μm refer specifically to the diameters of the glass or plastic cores of the cable (μm being the symbol of the micrometer or "micron" as it is typically refered to). The 125μm refers to the diameter of the cladding which surrounds the core of the cable.

The Difference

Below is a cross section of two types of multimode fibers (50/125μm and 62.5/125μm). The difference shown is primarily the core sizes which determine the available bandwidthfor the fiber. The smaller the core the higher the bandwidth.

Cross-Section of 62.5/125μm and 50/125μm Cables

Multimode fiber is typically available in different categories names OM1, OM2, OM3, OM4 and OM5. Only OM1 fiber is 62.5/125μm and is generally encased in an orange jacket for easy identification. Multimode fiber allows for multiple light modes to be propagated in the core at a given time. Different core sizes allow for variations in data transfer rates and transmission distances. The smaller the core the higher the data rate and the longer the transmission distance the fiber can be used for.

What is the Problem with Mixing Multimode Fibers?

There are two possible ways of mixing 50/125μm and 62.5/125μm multimode fibers. Either from 50/125μm to 62.5/125μm or from 62.5/125μm to 50/125μm.

Mixing Multimode Fibers

It is far more feasable to run from 50/125μm and 62.5/125μm as this combination is far less sensative to ofset and angular misalignment. Think of it as water running from a narrow hose into a slightly thicker one, the only real issue that may occur is what is known as link failure. 62.5/125μm to 50/125μm is not as successful as the light from the 62.5/125μm will bleed into the cladding surrounding the narrower 50/125μm fiber which results in coupling loss. If the loss is great enough the cable will be considered unsuccesful.

Combining 62.5/125μm and 50/125μm Cables

How Feasable is Mixing Multimode 62.5μm and 50μm Fibers?

As shown above you can do it, but should you? The short answer is no. While both 50μm and 62.5μm fibers are compatible with plenty of standard laser sources you should always plan for the worst and assume you will see a huge loss in your fiber when combining different fiber types. If you are in a pinch and feel that your network can handle the loss then feel free. Ideally if you are forced into this situation rather run 50µm to 62.5µm as the loss will be far less than the other way around.

The field of fiber optics is vast and contains hundreds of important terms that are extremely useful to understand when working in the industry.

Unfortunately, due to this vast number of terms we are unable to list them all. We have however done our best to compile a list that incorporates the most important terms used in the industry.

• Attenuation

  The reduction in optical power as it passes along a fiber, usually expressed in decibels (dB). See optical loss.

• Back Reflection

  That portion of fiber optic attenuation resulting of conversion of optical power to heat.

• Cable

  One or more fibers enclosed in protective coverings and strength members.

• Cladding

  The lower refractive index optical coating over the core of the fiber that "traps" light into the core. Connector: A device that provides for a demountable connection between two fibers or a fiber and an active device and provides protection for the fiber.

• Core

  The center of the optical fiber through which light is transmitted.

• Decibel (dB)

  A unit of measurement of optical power which indicates relative power on a logarithmic scale, sometimes called dB. dB=10 log (power ratio).

• Fiber optics

  Light transmission through flexible transmissive fibers for communications or lighting.

• Fusion splicer

  An instrument that splices fibers by fusing or welding them, typically by electrical arc.

• Insertion loss

  The loss caused by the insertion of a component such as a splice or connector in an optical fiber.

• Jacket

  The protective outer coating of the cable.

• Loss, Optical

  The amount of optical power lost as light is transmitted through fiber, splices, couplers, etc.

• Mechanical Splice

  A semi-permanent connection between two fibers made with an alignment device and index matching fluid or adhesive.

• Micron (*m)

  A unit of measure, 10-6 m, used to measure wavelength of light.

• Multimode Fiber

  A fiber with core diameter much larger than the wavelength of light transmitted that allows many modes of light to propagate. Commonly used with LED sources for lower speed, short distance links.

• Network

  A system of cables, hardware and equipment used for communications.

• Optical Fiber

  An optical waveguide, comprised of a light carrying core and cladding which traps light in the core.

• Optical Return Loss, Back Reflection

  Light reflected from the cleaved or polished end of a fiber caused by the difference of refractive indices of air and glass. Typically, 4% of the incident light. Expressed in dB relative to incident power.

• Refractive Index

  A property of optical materials that relates to the velocity of light in the material.

• Scattering

  The change of direction of light after striking small particles that causes loss in optical fibers.

• Single-mode Fiber

  A fiber with a small core, only a few times the wavelength of light transmitted, that only allows one mode of light to propagate. Commonly used with laser sources for high speed, long distance links.

• Splice (Fusion or Mechanical)

  A device that provides for a connection between two fibers, typically intended to be permanent.

• Termination

  Preparation of the end of a fiber to allow connection to another fiber or an active device, sometimes also called "connectorization".

• Total Internal Reflection

  Confinement of light into the core of a fiber by the reflection off the core-cladding boundary.

• Wavelength

  A measure of the color of light, usually expressed in nanometers (nm) or microns (*m)

With wireless networks dominating in both homes and businesses it's important to remember that wired networks can boost speeds to those actually promised by ISPs. Especially in the case of businesses having wired networks can lead to a large amount of incoming cables, one way to manage this properly is through the use of Patch Panels. Patch Panels help to centralize your cables making it far easier to work with and manage.

Types of Patch Panels

There are various types of copper and fiber patch panels available on the market. In this article we will be dealing primarily with copper patch panels which are designed for both shielded and unshielded copper cables such as the Cat5e, Cat6, Cat6a and Cat7. We with focus on the Cat5e.

Cat5e Patch Cables

Cat5e is simply put a basic copper Ethernet cable that is used to connect various devices. It is highly recommended that when connecting devices to a patch panel using Cat5e that use a good quality copper cable in either of its two basic types, booted or non-booted. Booted refers to the covering between the end connector and the cable itself. Non-booted cables are mostly only used when the cables with not be frequently unplugged. Check out the cables available from Fibertronics.

Cat5e Patch Panels

Copper patch panels used in a local area network (LAN) are mounted assemblies that have multiple ports in order to manage Ethernet cables. Patch panels are used to maximise network performance and help with network expansion and growth.

Patch panels are usually divided into 2 catagories, Shielded and Unshielded. Shielded Cat5e patch panels are designed for use in environments with high Electro Magnetic Interference (EMI) which can be caused by the presense of high power electrical cables. Unshielded patch panels are generally used when there is little to no EMI present.

In addition to these differences they can also be found in either Punch-down or Feedthrough configurations. In the case of a punch-down configuration the copper cables are connected to the the numbered RJ45 ports on the front plate. In the rear there are color-coded labels that are either designed for T568A and T568B wiring configurations that the connected cables are punched down into. Learn more about punching down by checking out the video below.

The feedthrough patch panels allow the cables to be connected to the RJ45 ports on the front plate and in the rear without the need to punch them down into the ports. This makes them great for high-density networks where addaptability is important.

Be sure to check out the Fibertronics Ethernet Patch Panels including Cat6 and Cat5e with full premium copper UTP, IDC, Krone, 110 RJ45 and 568 A/B compatibility

Traditional copper UTP/STP (Unshielded Twisted Pair/Shielded Twisted Pair) Ethernet cables are limited to 100 meters in length. To get around this and extend network connections we have Ethernet Media Converters.

What is a Media Converter?

As mentioned above, Ethernet Media Converters can be used to extend the distance between two network devices that use traditional copper cabling. They can also be used to convert electrical data signals into light pulses which can then be transmitted over fiber optic cables, thus further extending the range. Think of them as a bridge between copper network cables and fiber optic network cables.

Media Converters are able isolate both network nodes from each other and eliminate and ground loops or voltage spikes. This can be extremely useful when it comes to security as it makes in nearly impossible for anyone to tap into a line without detection.

Types of Media Converters

There are essentially 3 categories for media converters. These include Standalone Media Converters, DIN Rail Mount Industrial Converters and Chassis-based Media Converters.

Standalone Media Converte

 
Standalone converters are mostly used when only one or two conversions are needed in a network. Converting copper Ethernet into fiber, they support ultra-fast long-distance connections. Aside from extending a network they can also be great at saving both costs and space due to being standalone units as opposed to purchasing an entire chassis. Being small, they conveniently fit where needed making them suitable for environments such as telecoms cabinets or distribution boxes. This coupled with their plug-and-play design makes them an excellent choice.

Industrial Media Converters

 
Industrial Media Converters are designed for more heavy duty use in bigger applications. They are able to convert copper Ethernet from Single-mode to Multimode and Multimode to Multimode. Ideal for use in extending the distances of IP camera and wireless access points that can be found in things such as traffic management, oil and gas pipelines, weather tracking and industrial outdoor applications. The use very little power with low heat output all while offering great reliability and stability

Chassis-based Media Converters

Chassis-based Media Converters include a number of independent media converters on a chassis capable of holding up to 16 Media Converters. Think of them as a group of individual Media Converters, capable of longer signal transmission between multiple devices. All Media Converters in the system have their own casing and LED indicators with AC to DC power adapters. They themselves are hot-swappable making updating and replacement easy.

The individual Media Converters can be configured as either Managed or Unmanaged.

• Managed is extremely helpful in monitoring the statuses of all the Media Converters and power supplies within the chassis. This is achieved through the use of a Management Module that is available for installation into the chassis. The management follows industry standards, including SNMP (simple network management protocol) and HTTP, which allows monitoring from a third-party SNMP management workstation or via a web browser.
• Unmanaged makes it relatively easy when it comes to installation, however this can lead to problems later on as troubleshooting multiple Media Converters can be both time consuming and difficult.

Quick Summary

Media Converters allow for seamless integration between different network cable solutions. They support 10Mbps, 10/100Mbps, 100Mbps, 10/100/1000Mbps, Gigabit and 10 Gigabit.

Check out Fibertronics' range of Media Converters to find a solution that works for you, or call us on (321) 473 8933.

Insuring the integrity of fiber cable installations is crutial and this is done through accurate measuring and testing of fiber loss. Signal loss in fiber can result in unreliable and inconsistent transmissions.

Defining Fiber Losses

Fiber loss is also known as fiber optic attenuation or attenuation loss. Attenuation loss is measured by the amount of light lost between the input and output. A number of things can cause fiber loss and include; material absorbtion, fiber bending and connector loss.

Losses can be categorised into two basic groups. Intrinsic Loss and Extrinsic Loss. Intrinsic Loss refers to any loss that takes place due to things such as absorption loss, dispersion loss and scattering caused by the defects, Extrinsic Loss are caused by factors such as splicing loss, connector loss, and bending loss.

Standards for Fiber Loss

Standard regarding fiber loss have been developed by the Telecommunications Industry Association (TIA) and Electronic Industries Alliance (EIA) that specify performance and transmission requirements for fiber optic cables and connectors which are widely accepted throughout the industry. 

The maximum attenuation is actually the attenuation coefficient of fiber optic cable, which is expressed in dB/km. It is one of the most important parameters for fiber loss measurement. The maximum attenuation for different types of fiber optic cables (as defined by the TIA/EIA) are shown in the table below:

How to Calculate Losses in Fiber Optic Cable

For the various types of loss there are various fiber loss formulae that can be used, they are as follows;

• The Total Link Loss = Cable Attenuation + Connector Loss + Splice Loss

• Cable Attenuation (dB) = Maximum Cable Attenuation Coefficient (dB/km) × Length (km)

• Connector Loss (dB) = Number of Connector Pairs × Connector Loss Allowance (dB)

• Splice Loss (dB) = Number of Splices × Splice Loss Allowance (dB)

These formulae show that the total loss is the sum of the worst variables within the various fiber segments. (Please note that the loss calculated in this way is an estimation as there various factors that influence the results.)

MTP/MPO cables are used in a variety of high-speed, high-density applications and within larger data centers. Generally the quality of the cable is determined by the stability and sustainability of the network as a whole. So, how can you spot a quality MTP Cable in the wild?

Below are 5 things you should look for in MTP cables to ensure you get the quality you are looking for.

1. Branded Fiber Cores

MTP/MPO solutions are usually employed in networks where space is at a premium such as telecommunications distribution boxes and data center cabinets. When this happens it usuaslly results in small bend angle. If the fiber core is of poor quality the small bend angle can result in signal loss which leads to transmission interruptions. Brands such as Corning ClearCurve have a much better performance which reduces signal loss and makes routing and installation far easier.

2. Industry Recognized MTP Connectors

MTP connectors can house 12, 24, or 72 fibers in a ferrule. This makes them really grat for use in data centers due to the space they save. Industry recognized MTP or MPO connectors like those from US Conec, offers precision alignment which reduces insertion and return loss.

Industry recognised connectors provide a solid structure that make them great for many mating cycles. Buying the best MTP cables, and industry recognized MTP connectors matters greatly when quality and reliability are important.

3. Low Insertion Loss Is Very Important

Insertion Loss (IL) refers to the loss of optical power caused by using a connector or plug. It is one of the key factors that affects the performance of fiber optic networks. Simply put, the smaller the insertion loss, the better the network will perform. The IL of a conventional multi-mode MTP ferrule should generally not exceed 0.6 dB, and the conventional single-mode MTP ferrule should generally not exceed 0.75 dB. For single-mode and multi-mode MTP with low insertion loss (high quality), it is generally required that the insertion loss does not exceed 0.35 dB. When choosing MTP cables, try to choose vendors that provide insertion loss test reports with their cables. (Fibertronics does)

4. Consider How Flame Retardant It Is

Fiber optic cable jackets can be made up of various different materials, all of which have different fire resistances that are suitable for various scenarios. They most typically PVC, LSZH, Plenum and Riser. Most of these have good flame retardant properties. If there are higher requirements for the installation environment such as in drop ceiling and raised floors, it is best to choose a higher flame retardant level.

5. Stringent Quality Testing

The International Electrotechnical Commission (IEC) created IEC 61300-3-35 which is designed to ensure quality and performance. This standard oulines pass/fail requirements for connector end faces before connection. It has requirements relating to scratches and defects in each zone inside the connection. The defects include all non-linear features detectable on the fiber, including particulates, other debris, pits, chips and edge chipping. Basically put, the cleaner the end face is, the better the cable quality is overall.

All Fibertronics cables are subjected to testing within our advanced testing department that adheres to the highest quality standards. Once completed each cable has a print-out of it's test result bundled with it and is then ready to be carefully shipped to you.

With the now widespread use of high-speed fiber optic cables withing installations across the globe one of the biggest reported issues by installers is, without a doubt, is contaminated connectors. Dirty connectors are responsible for issues such as poor signal performance and outright connection failures.

Different Types of Fiber Optic Connectors

Without listing off all of the over 100 different types of fiber optic connectors, the most commonly used types include the following:

LC, SC, ST, FC, MT-RJ, E2000 and MTP/MPO.

If you'd like to learn more about these individual connectors be sure to check out our earlier blog titled A Quick Guide to Fiber Optic Connectors.

How Fiber Optics are Cleaned

There are two primary methods when it comes to the cleaning for fiber connectors: Dry Cleaning and Wet Cleaning.

Dry cleaning is mostly carried out using reel-types cassettes and push-type cleaners that wipe down the connector end faces with a dry cloth, in one direction.

Wet cleaning is seen as more 'aggressive' than dry cleaning and is great for removing airborne contaminants and oil residue. It is carried out by first wiping down the end face using a wet cleaning agent such as isopropyl alcohol and then drying it off to remove any additonal residue.

Below is a basic outline of the fiber optic cleaning process.

Important: Wet cleaning is not advised for recepticles and bulkheads as equipment damage can occur.

One of the most common questions we at Fibertronics often receive is, "Do I need a Fiber Optic Termination Box?" The first response is typically to ask what kind of fiber optic installation are you looking at building? This will determine if a box is required or not.

When You'll Need a Termination Box

If you're ordering or have an existing fiber optic assemby over two strands we highly recommend the use of a termination box as it helps prevent contaminents such as dust from interferring with your assembly's connectors. Not to mention it keeps all the cables extremely well organised, making them much easier to work on in future as you upgrade your assembley.

How They Work

As previously mentioned, termination boxes, as the name implies, are used when fiber optic cables are terminationed or have connectors added to the ends. A fiber optic assemby is typically fed into a termination box and then has the excess wrapped around a buil-in, internal cable spool before being connected into a fiber optic adapter panel. The fiber optic cable coming from your equipment is then connected to the other side of the adapter panel before exiting the termination box.

Which to Choose?

Fiber optic termination boxes are available in a variety of shapes, sizes and materials. Picking which one will work for your assembly will mostly depend on your own requirements such as number of fibers used and space available. 

Sometimes called Fiber Jumpers, Patch Cords are used to connect network devices or end devices to a cabling system. These cables generally have various connectors that can be applied to each end. These include; LC, SC, ST or MTRJ connectors. Available in simplex (single cord) or duplex (dual cords) depending on your network requirements. It can be difficult to select which of the variations might best suit your application best.

Fiber Modes

Before making use of fiber optic patch cords you should ensure that the wavelength of the tranciever module at the end of the cable is identical. This means that the specified wavelength of the light emitting module (your device), should be the same as that of the cable you intend to make use of. There is a very simple way to do this. 

Short wave optical modules require the use of a multimode patch cable, these cables are typically covered in an orange jacket. Long wave modules require the use of single-mode patch cables which are wrapped in a yellow jacket.

Simplex vs Duplex

Simplex cables are required when data transmission is required to be send in one direction along the cable. It's one way traffic so to speak and is primarily used in applications such as large TV networks.

Duplex cables allow for two way traffic in that they have two fibers stands within a single cable. You can find these cables being used in workstations, servers, switches and on various pieces of networking hardware with large data-centers.

Typically duplex cables come in two types of construction; Uni-boot and Zip Cord. Uni-boot means that the two fibers in he cable terminate in a single connector. These are generally more expensive than the Zip Cord cables which have the wo fiber stands placed together, but they can be easily seperated. 

Which to Choose?

Simplex Patch Cord is great for sending data tansmissions over long distances. It does not require a lot of materials to manufacture and this inturn keeps the cost down when compared to duplex cables. They are incredibly good when it comes to capacit and high transmission speeds meaning higher bandwidth and because of this are very common in modern communications networks.

Duplex Patch Cords are great when it comes to keeping this neat and organised as less cables are required, making them easier to maitain and sort. They are however not as great over longer distances and high bandwidths.

Looking After Your Patch Cords

One of the most import things to consider when making use of patch cords is not to exceed their maximum bend radius. They are, after all, glass stands encased in PVC jackets and can quite easily break if pushed too far. Additionally, ensure that they are always used within optimal conditions and not subject to excess stress by things such as, temperature, moisture, tension stress and vibrations.