Loose tube fiber and tight buffered differences (2023)

Tight buffered and loose tube fiber are the two styles of constructions Fiber optic cables offered. Between them, there are several common denominators, like the fact that both have in their interior a strengthening member of sorts that can be made of stainless steel in the form of wire strands, aramid yarn or gel-filled sleeves.

Even though they might have similarities of construction between them, they are each designed for specific environments.

Loose Tube Fiber

This type of cable is designed for the outdoors. Cables that are on the outside are continuously stressed by a plurality of environmental conditions that could affect their integrity and performance.

Loose tube fiber and tight buffered differences (1)

Temperature changes, ice and wind loading, thermal shock, moisture, and humidity are some of the environmental conditions to which a cable can be subject. It’s no wonder it must be resistant to the very core, in order to preserve and protect the optical properties of the fibers within.

The fiber core, coating, and cladding are all very well protected by being enclosed in semi-flexible tubes that function as protective sleeves.

These cables tend to hold several optical fibers at a time, loosely bundling them up in an outer jacket that encompasses everything inside.

Notice the following:

Loose tube cables con also be found filled with a water-resistant gel that surrounds every fiber it contains.

This gel’s main purpose is to protect the fibers from moisture which makes them the ideal choice if you happen to live in a harsh environment with high humidity where H2O and water condensation can be a major problem.

(Video) What is Fiber Optic Cable Part 4: Indoor Outdoor Rated Tight Buffered

If drastic temperature changes also affect your environment, loose tube, gel-filled cables will do the trick since they also have the ability to expand and contract when the temperature fluctuates.

If the cable will have to be submerged in water or cover a plurality of bends, then perhaps you might want to consider other options. The strain and pressure from water or recurrent bending just might impel the fibers to protrude from within the get and be left exposed which definitely isn´t good.

Tight-buffered cables

Loose tube fiber and tight buffered differences (2)

These cables differ from loose tube ones in several aspects. For starters, the fiber core isn´t protected by a gel layer nor any sort of sleeve.


the core is protected by a two-layer or double coating, consisting the first of plastic and the second of waterproof acrylate.

Moisture is barred from entering the cable and affecting the core thanks to the acrylate coating much like the gel that fills the sleeve of loose-tube cables protects the core from humidity and moisture.

The difference lies in that the acrylate coating never allows the core to be exposed when it’s bent or compressed underwater since it tightly wraps the plastic fiber layer that covers it.

Tight-buffered cables are mostly used for indoor applications and their sturdiness makes them the ideal choice for LAN/WAN connections of moderate length, long indoor runs or even ones that need to be directly buried as well as applications that are under water.


(Video) Loose Tube & Tight Buffer

These cables are a lot easier to install than their loose-tube counterparts since they don’t need any sort of gel (which can be quite messy and a nuisance to clean up) for their installment.

Another perk is that there’s no need for a fan-out kit for splicing or termination. The connectors can be crimped directly to each fiber. Yeah!

Fiber cable termination

Adding a connector to each and every optical fiber in a cable is of what fiber cable termination consists. Without it, the fibers wouldn’t be able to be attached to any other equipment thus defeating their purpose of transmitting data and information.

The most popular solutions in terms of fiber cable termination are breakout kits, pigtails, and splicing.

Fiber optic terminations (where cables end) are made two ways:

  • Using connectors that marry two fibers creating a temporary joint and/or connect the fiber to a piece of network gear.

  • Splicing which creates a permanent joint between two fibers.

Whether connecting or splicing a fiber optic cable, either one must have both of the following:

  • High mechanical strength.

  • Great optical performance which entails low data loss and minimal reflectance.

Bear in mind that all terminations must be compatible with the equipment to which they will be connected and must also be protected against environmental issues or hazards that are present at the place of installment.

The most common connectors for fiber optic cables are male connectors (also known as plugs) that have a protruding ferrule which holds the fibers and aligns two cables for mating.

A mating adapter is used to concatenate the two connectors that must fit the securing mechanism they use (bayonet, screw-on or snap-in.) If you want to connect the cable directly to active devices like LEDs, VCSELs, and detectors, the ferrule design is your best bet.

(Video) Fiber Optic Cable 250um and 900um buffer comparison and overview

Single-mode and multi-mode fibers each use different connectors and termination procedures.

The easiest to terminate are multimode fibers which are usually done by installing connectors directly on it whereas single-mode terminations are most likely made by splicing a pigtail onto the installed cable instead of terminating the fiber directly as you would usually find on multimode fiber.

Terminations used on single-mode cables demand extreme care while assembling in order to ensure the best performance possible. That’s why they are usually done in an industrial facility with an epoxy that has been heat-cured along with some machine polishing.

When faced with the task of choosing a connector type, take into consideration the following aspects:

  1. Make sure the connector is compatible with the systems that are being used.

  2. Do some research about the entire installation process if you are not familiar with it.

  3. Be sure to investigate the pros and cons of each possible connector type before committing to a specific one.

Breakout Kits

A breakout kit is basically a set of empty jackets that have been designed to offer protection to tight-buffered strands of fiber from a cable that is fragile. This method of termination requires no splicing nor does it demand the use of a splicebox which is basically a protective enclosure for the cable ends.

When using fiber distribution cable, loose-buffer and/or ribbon cable, this is the most common termination choice because these types of cable contain multiple strands that are designed for it to be permanent.


This is a single, short, usually tight-buffered, optical fiber that boasts having an optical connector previously installed on one end and a length of exposed fiber at the other, which basically means it only has one connector on one end of the cable.

The end of the pigtail is stripped and then fusion spliced to a single fiber of a multi-fiber trunk. The pigtails are then spliced to each fiber in the trunk which ultimately "breaks out" the multi-fiber cable into the fibers that compose it for connection to the end equipment.

(Video) How to strip loose tube and tight buffered fiber?

Pigtails can have either male or female connectors. Male connectors can be directly plugged into an optical transceiver whilst female connectors can be mounted bay two and two in a patch panel. If in pairs doesn’t work for you, they can also be mounted in single-fiber solutions that offer the possibility of connecting them to endpoints or fiber runs that use patch fibers.


Splicing two fiber optic cables together offers a permanent or semi-permanent connection between them. There does exist fiber optic splicing solutions that can be disconnected but this connecting method was not intended for connecting/disconnecting on a regular basis.

Fiber optic splicing is used when a more permanent solution is needed to fix a connection problem. For example, if you need to run a 10km length cable. Most fiber optic cables are made in maximum lengths of 5km so you´ll probably need to splice to cables together in order to achieve the desired run. In such cases, connectors are not an option.

There are two ways fiber optic splicing can be done:

Mechanical splices: this kind of splicing is normally used when a quick solution is needed.

You just need to strip back the protective layer that surrounds the fiber optic cable, clean it making sure there are no pieces of plastic or dust and the cut the fiber with precision and a firm hand, making sure that the angle of the cut has the same angle regarding the axis of the fiber. Something to bear in mind: this type of slicing can cause up to a 10% light loss.

Fusion splices: as the name indicates, this type of splicing is made by fusing (or melting) two fiber optic cable ends together. In order to obtain this type of connection, an electric arc is needed to weld the two ends together. It also requires that you know exactly what you are doing. If you don´t, leave it to the professionals since specialized equipment will be needed.

You can check the whole process of a loose tube fiber preparation for termination here:

(Video) Fiber cable construction, loose and tight buffered cables


What is the difference between loose tube and tight buffered fiber? ›

The fundamental difference between tight buffered and loose tube fibre cables is the construction of the fibre optic cable. In tight buffered cables, there isn't a gap between the fibre cores' coating and cladding layers. Whereas loose tube fibre cables have a gap, either filled with gel or are loose in the cable.

What are the advantages of loose buffer tube fiber? ›

The loose buffer tube offers lower cable attenuation from microbending in any given fiber, plus a high level of isolation from external forces. Under continuous mechanical stress, the loose tube permits more stable transmission characteristics.

What is tight buffered fiber cable? ›

Tight Buffered Fibre Cable

This structure protects individual fibres during the handling, routing and connecting process. The main use of tight buffered cables, also known as riser cable or fibre distribution cable, is within buildings and campuses, and are generally installed on cable trays or in conduits.

What does loose tube fiber mean? ›

Loose tube fiber contains multiple strands of fiber in a single jacket. Since the fibers are “loose” inside the jacket, outside forces are less likely to reach the fibers. This makes it the more durable option of the two.

Where is loose tube fiber used? ›

Loose Tubes (loose tube cables): Small, thin plastic tubes containing as many as a dozen 250 micron buffered fibers used to protect fibers in cables rated for outside plant use. They allow the fibers to be isolated from high pulling tension and can be filled with water-blocking materials to prevent moisture entry.

What is the difference types of fiber connectors? ›

The most commonly used connectors today are ST, SC, FC, MT-RJ, & LC connectors while Plastic FOC, Opti-Jack, LX-5, Volition, MU, and E2000 are less used options. Finally, MPO / MTP connectors are fiber connectors that have become widely used in today's data centers.

Does tight buffered fiber need fan out kits? ›

Another perk is that there's no need for a fan-out kit for splicing or termination. The connectors can be crimped directly to each fiber.

What is the purpose of a buffer tube? ›

Buffer tubes are an aluminum housing attached to the rifle's lower receiver, and they contain the AR15 buffer and the recoil spring. They also act as a mounting point for the buttstock or pistol brace. There are different types of buffer tubes available on the market, and they both function well in firearms.

What are the two types of buffer tubes? ›

Mil-Spec vs.

Carbine length buffer tubes are available in two styles: Mil-Spec and Commercial spec. Mil-Spec buffer tubes are designed to a certain standard that is universal across the U.S. military. So, any buffer tube labeled "Mil-Spec" is the same.

What are the two types of fiber cables? ›

There are two primary types of fibre – multimode and singlemode.

What are the 3 common variations of fiber cable? ›

There are three types of fiber optic cable: single mode, multimode and plastic optical fiber (POF).

What are the three types of fiber optic connections? ›

Types of Fiber Optic Connector

In the USA for networking and audio/video, the three most popular styles are LC, SC, and ST. LC and SC tend to be the most commonly used styles. Today, ST connectors are seeing more limited usage.

What is a fiber buffer tube? ›

Loose buffer tubes house and protect optical fibers in long-distance terrestrial, undersea, and aerial cables. They form an inner barrier to water penetration and help isolate the fibers from vibration and thermal extremes. Cables can have as many as 24 color-coded buffer tubes, each containing up to 12 fibers.

What is the diameter of tight buffer? ›

Tight buffer or tight tube cable designs are typically used for ISP applications. Each fiber is coated with a buffer coating, usually with an outside diameter of 900m.

Can you Ribbonize loose tube fiber? ›

For ribbonizing loose tube fibers, Prysmian recommends the use of either the AFL, Sumitomo, or USCONEC fiber arrangement tools. The kits are compatible with major commercially available mass fusion splicers. Always follow the tool kit manufacture procedures and practices when ribbonizing fiber.

How many fibers in a buffer tube? ›

From 1 to 12 fibers are placed within color-coded buffer tubes, which are several times larger than fibers. To prevent water intrusion, the buffer tubes are filled with compounds.

Why is loose tube construction preferred when cables must be pulled through ducts? ›

Loose tube cables are the most widely used cables for outside plant trunks because it offers the best protection for the fibers under high pulling tensions and can be easily protected from moisture with water-blocking gel or tapes.

What are the two types of fiber optic cable and where are they commonly used? ›

There are two types of fibre optic cables – multimode and single-mode. Multimode optical fibre or OFC is capable of carrying multiple light rays (modes) at the same time as it has varying optical properties at the core. Single-mode fibre has a much smaller core size (9 microns).

Which is the best method for connecting two fiber? ›

Splicing in the Field

This offers the best quality connection of all in-field options in that the fiber ends are lined up and welded together. No excess cable is left over when the process is complete.

What are the 3 types of connectors? ›

Electrical connectors are classified into three types based on their termination ends: board-to-board connectors, cable/wire-to-cable/wire connectors, and cable/wire-to-board connectors.

What are two types of optical fiber terminations? ›

There are two types of fiber terminations: connector and splicing.

How much buffer tube and fiber slack should be provided? ›

What is the minimum amount of slack that must be provided for splicing fiber-optic cable in underground installations? 15 meters on both the inbound and outbound span.

What type of fiber requires a fan out kit? ›

Fan Out or Break Out Kits are used when terminating fiber optic cables that are made with subunits that contain color coded bare fibers rather than tight buffered fibers.

Can you run fiber and power together? ›

Yes, fiber can be run near power. Fiber signal is transmitted as light which does not experience the same interference issues as other electrical signals.

What is the purpose of a buffered solution and why is this important? ›

A buffer is a solution that can resist pH change upon the addition of an acidic or basic components. It is able to neutralize small amounts of added acid or base, thus maintaining the pH of the solution relatively stable. This is important for processes and/or reactions which require specific and stable pH ranges.

Which buffer is most important and why? ›

The Carbonic Acid-Bicarbonate buffer system is the most important buffer for maintaining the pH homeostasis of blood. In this system, gaseous metabolic waste carbon dioxide reacts with water to form carbonic acid, which quickly dissociates into a hydrogen ion and bicarbonate (see below).

What are the 3 types of buffer systems? ›

The body's chemical buffer system consists of three individual buffers: the carbonate/carbonic acid buffer, the phosphate buffer and the buffering of plasma proteins.

What are the two components of a buffer system? ›

A buffer must contain a weak acid and its conjugate base. There are several ways a solution containing these two components can be made: Buffers can be made from weak acids or base and their salts.

Does a heavier buffer reduce recoil? ›

A heavier buffer will reduce recoil, while a lighter buffer will increase it. You will also need to take into account the type of ammo you are using. Heavier buffers are needed with slow-moving rounds, while lighter buffers are ideal for high-velocity ammo.

What are the different fiber modes? ›

There are basically three types of optical fiber: single mode, multimode graded index, and multimode step-index. They are characterized by the way light travels down the fiber and depend on both the wavelength of the light and the mechanical geometry of the fiber.

What are the 2 most common types of cable connectors? ›

Twisted pair cabling comes in two varieties: shielded and unshielded. Unshielded twisted pair (UTP) is the most popular and is generally the best option for school networks (See fig.

What kind of fiber cable does AT&T use? ›

If you see the 300, 500 or gigabit speed tiers offered at your address, you can access AT&T's fiber internet service, which uses 100% fiber technology.

What are the 4 types of fiber optic cable? ›

The common types of fiber optic connectors are LC, SC, MTP/MPO, ST, and FC. LC connector, as a main fiber optic connector, tends to be the most preferred one due to its compact size, high performance, and ease of use.

How can you tell if a fiber is single mode or multimode? ›

A: Apart from the Bale Clasp color coding, single-mode and multimode fiber cables can also be identified by the color of the patch cord. In single-mode optical fiber cable, the patch cord is in yellow color; and in multimode fiber cable, the patch cord comes in orange color.

What are the 4 types of optical fiber cable construction? ›

Fibre optic cable construction
  • Core. This is the physical medium that transports optical data signals from an attached light source to a receiving device. ...
  • Cladding. ...
  • Coating. ...
  • Strengthening fibres. ...
  • Cable jacket.

What are the two main methods of fiber optic splicing? ›

There are 2 methods of splicing, mechanical or fusion. Both methods provide much lower insertion loss compared to fiber connectors.

What is loose tube vs tight buffered? ›

The fundamental difference between tight buffered and loose tube fibre cables is the construction of the fibre optic cable. In tight buffered cables, there isn't a gap between the fibre cores' coating and cladding layers. Whereas loose tube fibre cables have a gap, either filled with gel or are loose in the cable.

What is the purpose of buffer tubes in fiber optic cable quizlet? ›

What is the purpose of buffer tubes in fiber-optic cable? Buffer tubes protect and separate the optical fibers in smaller bundles.

What is the diameter of the optical fiber after buffer coating? ›

The most common cladding diameter is 125 µm. The material of buffer coating usually is soft or hard plastic such as acrylic, nylon and with diameter ranges from 250 µm to 900 µm. Buffer coating provides mechanical protection and bending flexibility for the fiber.

What is the size of the buffer coating in OSP? ›

OSP cables are constructed around the smaller 250-micron buffered fibers to allow packing as many fibers into the cable as possible while keeping the cable outside diameter as small as possible.

In which application would you not normally use loose tube fiber? ›

Although loose-tube cables are subject to tough environmental conditions, they are not applicable when cables need to be submerged or where cables are routed around multiple bends.

What size is loose tube fiber? ›

A 144 fiber loose tube cable is typically 15-16mm diameter while a comparable micro cable is only about 8 mm diameter - half the size and about one-third the weight. The smaller size allows for much larger fiber counts, over 3,000 fibers in some designs.

What are the three types of fiber misalignment? ›

The principal source of loss in both connectors and splices is fiber-to-fiber end face misalignment. There are three types of misalignment loss which may occur individually or in combination. These are lateral misalignment, axial separation, and angular misalignment.

What are the four types of fiber optic connectors? ›

The common types of fiber optic connectors are LC, SC, MTP/MPO, ST, and FC. LC connector, as a main fiber optic connector, tends to be the most preferred one due to its compact size, high performance, and ease of use.

Do you need a fan-out kit for tight buffer fiber? ›

Another perk is that there's no need for a fan-out kit for splicing or termination. The connectors can be crimped directly to each fiber.

What are the 2 classifications of fiber? ›

There are 2 different types of fiber -- soluble and insoluble. Both are important for health, digestion, and preventing diseases. Soluble fiber attracts water and turns to gel during digestion. This slows digestion.

What are the two main types of misalignment? ›

There are two types of misalignment: offset or parallel misalignment and angular, gap, or face misalignment. With offset misalignment, the center lines of both shafts are parallel but they are offset. With angular misalignment, the shafts are at an angle to each other.

What is the purpose of buffer tubes in fiber optic cable? ›

Loose buffer tubes house and protect optical fibers in long-distance terrestrial, undersea, and aerial cables. They form an inner barrier to water penetration and help isolate the fibers from vibration and thermal extremes. Cables can have as many as 24 color-coded buffer tubes, each containing up to 12 fibers.

What is the typical amount of slack allowed on any fiber optic cable? ›

Fiber Optic Cable Slack. A small amount of slack cable (20-30 feet) can be useful in the event that cable repair or relocation is needed.

What are the 3 basic components of an optic fiber system? ›

The three basic elements of a fiber optic cable are the core, the cladding and the coating. Core: This is the light transmission area of the fiber, either glass or plastic.


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