Fiber Optic Pigtail Introduction and Installation Guide

The success of a network in fiber optic cable installation heavily relies on how the cables are connected to the system. When this process is executed correctly, optical signals can flow through the link with minimal attenuation and return loss. Fiber optic pigtails provide an optimal solution for joining optical fibers, particularly in 99% of single-mode applications. This post will cover fundamental information about fiber optic pigtails, encompassing various pigtail connector types, classifications, and fiber pigtail splicing techniques.

  

What is Fiber Pigtail?

  

The fiber optic pigtail is a type of fiber optic cable with a pre-installed connector on one end while the other remains unterminated. This configuration allows the connector side to easily connect to equipment while the other end can be fused or mechanically spliced with other optical fiber cables. Fiber optic pigtails are crucial in terminating fiber optic cables using fusion or mechanical splicing methods. When high-quality pigtail cables are combined with proper fusion splicing practices, they deliver optimal performance for fiber optic cable terminations. You can commonly find fiber optic pigtails in fiber optic management equipment such as Optical Distribution Frames (ODF), fiber terminal boxes, and distribution boxes.

  

The Difference Between Fiber Pigtail vs. Fiber Patch Cord

 

The fiber optic pigtail is a cable with a fiber connector installed at one end, leaving the other unconnected. In contrast, fiber optic connectors are terminated at both ends of a fiber patch cord. Patch cord fibers are typically jacketed, while fiber pigtail cables are usually unjacketed because they are spliced and protected within a fiber splice tray. A fiber patch cord can be cut into two pieces to create two pigtails. Some installers prefer this approach to avoid the challenge of testing pigtail cables in the field. Instead, they push the performance of a fiber patch cord and then divide it into two fiber pigtails if needed.

 

How to Classify Different Types of Fiber Pigtails?

 

Fiber optic pigtails come in several types. They can be categorized based on their connector type, including LC fiber optic pigtails, SC fiber pigtails, and ST fiber pigtails. Another classification is by fiber type, which includes single-mode fiber optic pigtails and multimode fiber optic pigtails. Additionally, pigtails can vary in fiber count, with options such as 6 and 12 fibers available in the market.

 

Figure 1: Fiber Optic Pigtail

 

By Fiber Type

 

Fiber optic pigtails are divided into two main types: single-mode (colored yellow) and multimode (colored orange) fiber. Multimode fiber optic pigtails use bulk multimode fiber cables with either 62.5/125 micron or 50/125-micron specifications, terminated with multimode fiber optic connectors at one end. Additionally, 10G multimode fiber cables (OM3 or OM4) are available in fiber optic pigtails, usually distinguished by an aqua jacket color.

 

On the other hand, single-mode fiber pigtail cables utilize 9/125 micron single-mode fiber cables and are terminated with single-mode fiber connectors at one end.

 

By Connector Type

 

A variety of fiber optic pigtails are available. each terminated with a different connector. Commonly used pigtail cable connectors encompass a range of options, such as LC fiber pigtail, SC fiber pigtail, ST fiber pigtail, FC fiber pigtail, MT-RJ fiber pigtail, E2000 fiber pigtail, and others. Each connector has advantages and is suitable for different applications and systems. Let's take a closer look at some of the commonly used ones:

 

SC Fiber Optic Pigtail: The SC pigtail cable connector features a non-optical disconnect design with a 2.5mm pre-radiused zirconia or stainless alloy ferrule. SC fiber pigtail is known for its cost-effectiveness and widespread use in CATV, LAN, WAN, test, and measurement applications.

 

FC Fiber Optic Pigtail: The FC fiber pigtail utilizes the metallic body of FC optical connectors and has a screw-type structure with high-precision ceramic ferrules. FC fiber optic pigtails and related products find wide application in general fiber optic connections.

 

ST Fiber Optic Pigtail: The ST pigtail connector is particularly popular for multimode fiber optic LAN applications. It has an extended 2.5mm diameter ferrule made of ceramic (zirconia), stainless alloy, or plastic. ST fiber pigtails are commonly utilized in telecommunications, industry, medical, and sensor applications.

 

Fiber optic pigtails, just like fiber optic patch cords, are offered in both UPC and APC variations. Common types include SC/APC pigtail, FC/APC pigtail, and MU/UPC pigtail.

 

Figure2: SC/UPC 9/125 Singlemode fiber optic pigtail

 

By Application Environment

 

There are specialized pigtail cables, known as armored fiber pigtails and waterproof fiber pigtails, designed to withstand harsh and extreme environments.

 

Armored Pigtail: Armored fiber optic pigtails are constructed with a stainless steel tube or other strong steel material inside the outer jacket. This design provides extra protection for the fiber and enhances the overall network reliability. It also helps prevent damage caused by rodents, construction work, or the weight of other cables.

 

Waterproof Pigtail: Waterproof fiber pigtail is designed with a stainless steel strengthened waterproof unit and an armored outdoor PE (Poly Ethylene) jacket. This pigtail type is well-suited for harsh environments such as communication towers, CATV installations, and military applications. The waterproof pigtail cable offers excellent toughness, tensile strength, and reliable performance, making it ideal for outdoor connections.

 

By Fiber Count

 

Fiber optic pigtails come in various strand fiber counts, such as 1, 2, 4, 6, 8, 12, 24, and 48 strands. The design of the pigtail depends on the fiber count:

 

Simplex Fiber Optic Pigtail: This type contains one fiber and a single connector on one end.

 

Duplex Fiber Optic Pigtail: A duplex pigtail features two fibers and two connectors on one end, with each fiber usually marked as "A" or "B," or using different colored connector boots to indicate polarity.

 

Similarly, pigtails with 4, 6, 8, 12, 24, 48, and even more than 48 fibers have their respective features, accommodating the specific needs of various applications and systems.

 

Note: Fiber pigtails have either female connectors (used in patch panels for easy connections) or male connectors (directly plugged into optical transceivers for signal transmission).

 

Fiber Optic Pigtail Splicing: Swift and Effortless Fiber Termination

 

Fiber pigtail offers high-quality performance as its connected end is factory-attached, ensuring greater precision than field-terminated cables. This pigtail can be spliced to optical fibers using either fusion or mechanical splicing methods. Fusion splicing allows for quick attachment, taking just a minute or less when using a fusion splicer, saving significant time and costs in field termination.

 

Mechanical fiber optic pigtail splicing precisely aligns a pigtail and fiber patch cord, creating a joint that can be temporary or permanent, facilitating light transmission between fibers. To account for potential splicing errors, ordering a slightly longer fiber pigtail assembly than needed is advisable, providing extra slack for corrections. Additionally, choosing fiber pigtail assemblies with reliable quality simplifies the splicing process.

 

 

Figure 3: Mechanical Splicing vs Fusion Splicing

 

Conclusion

 

Fiber optic pigtails serve the essential purpose of splicing fibers to connect them with patch panels or equipment. They offer a practical and dependable solution for simplified fiber termination, resulting in significant time and labor savings during installation. If you want to buy fiber optic pigtails or other optical fiber products, you are welcome to contact QSFPTEK via [email protected].