Fiber Optic Cabling Termination Styles and Tools

While many industries have faced stagnation or recession in recent years, the fiber optic cabling sector has been experiencing significant growth. This surge can be attributed to the increasing demand for high-bandwidth applications and the recognition that traditional copper cabling is reaching its limitations. 

Moreover, outdated perceptions of fiber optic technology as fragile, difficult to install, or expensive have given way to a new understanding. Professionals from various fields, ranging from homeowners to network managers and system engineers, have discovered that fiber optic cabling and technology are more accessible and practical than ever before. 

Additionally, Fiber to the Premises (FTTP) has brought fiber optic technology to the forefront of people's minds. 

Presently there is a growing need for fiber optic cabling installations both inside and outside plant, horizontal or vertical. No matter what segment of the industry you are from, it is important to stay current on Trends in Fiber Optic Cabling Termination Styles and Tools.

This article explores the current trends in fiber optic cabling termination styles, how they may benefit you if you are running or starting a fiber installation business, and utilizing MTP/MPO for 40G or 100G network speeds.

History of different styles of termination methods

The fiber optic cabling industry has witnessed numerous connector and termination method innovations since the late 1970s. Each new development aimed to offer improved performance and easier, more cost-effective termination methods than the previous ones. 

Early fibers were fragile and challenging to work with, and epoxy connectorization was the norm. 

Over time, hot-melt and anaerobic epoxies simplified termination, but polishing was still required, affecting yield. Crimp-type connectors without epoxy were unreliable and eventually phased out. 

Mechanical field splices coexisted with epoxy/polish connectors until the emergence of "No-Epoxy/No-Polish" connectors. 

These advancements have simplified and improved fiber optic termination methods.

"No-Epoxy/No-Polish" connectors (mechanical) have become more popular for various applications, but there are draw backs such as temperature and humidity fluctuations that may lead to issues.

Fusion splicing machines have become more cost-effective, compact, and efficient, making pre-terminated/fusion splice connectors attractive for demanding applications. 

These advancements help reduce losses and enhance reliability.

Styles of Terminations (the basics)

There are different options to terminate fiber optic cables.  Below is a chart that summarizes the main methods that installers of fiber optic cables may employ, depending on their level of expertise and familiarity with the methods.  

Another factor to consider is the cost associated with each method.  The more scientific methods, such as fusion splicing, are often the best, yet require equipment that may cost thousands of dollars.  The cheaper methods may be more practical for everyday installers, but the long term cost of having to redo jobs because the cheap route was taken may make up for the cost of getting it done the right way the first time.

With a high level over view of each point covered, let’s now go into each method in more depth.

Mechanical Splicing vs Fusion Splicing

The choice between mechanical splicing and fusion splicing plays a pivotal role in the world of fiber optic termination. 

Understanding the nuances and advantages of each method is essential for making informed decisions in the field. 

Neither approach is better than the other, but you may find one more closely suits your needs for an installation.

No Epoxy/No-Polish Connectors

The introduction of factory pre-termination brought a significant advantage to those involved in field installations. 

These pre-polished and mechanically spliced connectors eliminated most of the learning curve, the need for consumables, and the issues related to low yield that were associated with previous designs. They consist of a fiber optic connector with a short section of fiber that is factory terminated and polished on one end. 

Inside the connector body, the other end of the fiber features a perfectly cleaved fiber with an optical matching gel, essentially simulating a mechanical splice.

A crucial aspect of achieving a perfect termination relies heavily on inserting a perfectly cleaved piece of fiber, which, when combined with the optical matching gel and the internally factory cleaved and polished section of the fiber, results in a reliable splice and a relatively low-loss connector assembly. 

These No-Epoxy/No-Polish connectors are available in OM1, OM2, OM3, and Singlemode.

This illustration shows the basis for the No-Epoxy/No-Polish" connectors (mechanical splice type)
Image by Corning

In the past, terminating connectors onto Singlemode cable in the field was seen as impractical. For many years in the evolution of modern fiber optic termination, it was common practice to fusion splice "pigtails" with connector ends that were factory pre-terminated onto the Singlemode fiber strands. This practice ultimately led to the development of Fusion Splice connectors.

Their evolution has been extensive, rendering them more dependable for most applications. Notably, Corning has reported the sale of 45 million units since their introduction in 1993. 

These user-friendly connector systems are now widely available from multiple manufacturers and have gained substantial popularity in the field, particularly for applications in Multimode LAN and other field scenarios.

That being said, we believe they are a less reliable termination style as over time there may be fluctuations in temperature and humidity, both indoor and outdoor, that may lead to issues.

Fusion Splice Connectors

Instead of relying on a mechanical splice described above, fusion splice connectors are bonded to their fibers using the electric arc process known as fusion splicing. 

Modern fusion splicing delivers nearly the same level of performance as an unbroken fiber strand, both in terms of minimizing signal loss and enhancing the cable's tensile strength.

Fusion connector systems are specifically designed for high-end applications that demand the most robust terminations, capable of withstanding even the harshest conditions. 

More significantly, they virtually eliminate back reflection, a critical consideration in demanding Singlemode applications.

This illustration shows the basis for the Fusion Connector 

Image by Corning

How pricing has changed over the years

The significant drop in the cost of Fusion Splicing Machines, in line with the trend of technological advancements, has led to the emergence and growing popularity of Pre-Polished/Fusion Splice connectors in the market. 

A decade ago, fusion splicers were large, unwieldy, and came with a hefty price tag of around $25,000. Today, these machines have undergone a transformation, becoming smaller, lighter, and more efficient, with prices ranging from $7,000 to $12,000 or even higher. 

This transformation has been facilitated by the increasingly stringent fiber tolerances achieved over the past decade. 

As a result, the more budget-friendly "cladding alignment" type fusion splicers have become widely accepted for critical tasks. While not inexpensive, fusion splicing machines can readily justify their cost and yield a return on investment in high-end or high-volume applications.

Which should you choose for a fiber installation start up?

In contrast to copper cabling, which is accompanied by relatively inexpensive tooling, the startup costs for fiber optic termination tend to be notably higher. Typically, toolkits required for most No-Epoxy/No-Polish (mechanical) systems fall within the range of approximately $700.00 to $2,000.00, with an average cost around $1,500.00. 

Price Per Connector Comparison

These toolkits generally include a high-quality cleaving machine, a proprietary locking (or crimping) device, and various tools and accessories necessary for fiber stripping and handling.

It's important to note that these systems often come with proprietary components, limiting compatibility to a particular manufacturer's brand of connectors. Consequently, choosing a system demands careful consideration. 

For instance, if your requirements involve terminating ST connectors and the selected system does not support them, you would need to invest in an entirely different platform.

As mentioned earlier, fusion splicing machines required for No-Epoxy/No-Polish (fusion) systems can be relatively costly to purchase, typically ranging from $7,000 to $12,000 or even higher. As an alternative, some individuals opt to rent these machines on an as-needed basis.

Factory Pre-Terminated Assemblies

Due to high startup costs of all other field termination systems, combined with the need for quality field installation of fiber, Factory Pre-Terminated assemblies have gained steadily in popularity over the past five years. 

Surprisingly even so with many veteran installers who are capable of epoxy/polish termination. 

Below is a chart that exemplifies some of the reasons for this shift. 

NOTE: Termination time does not take into account setup time

Many providers of Factory Pre-Terminated assemblies offer the option to tailor them to your specific needs, allowing customization in terms of fiber type, length, fiber count, connector style, and more. 

The most commonly requested connector styles include ST, SC, LC, and MTP/MPO. Additionally, many vendors offer breakouts with 2 mil or 3 mil color-coded buffer tubes as standard features. 

A high-quality Pre-Terminated assembly is typically accompanied by a comprehensive test report that displays dB loss data for all individual strands.

These assemblies have a well-established history in the world of fiber optics, with construction methods that have evolved over the years, resulting in a proven track record of high installation success rates. QuickTreX, for instance, asserts a remarkable 99.8% success rate based on 13 years of sales data.

Adapting to Network Speeds of 40 Gb/s and 100 Gb/s Ethernet

In June 2010, the IEEE introduced the 802.3ba standards for 40Gb/s and 100Gb/s Ethernet. These cutting-edge network speeds rely on the utilization of OM3 and OM4 fiber types. 

However, in practice, OM3 and OM4 fibers can only deliver data speeds of 10 Gb/s per 2-fiber channel due to existing electronic constraints. 

To achieve the required speed, a solution known as "Parallel Optics" divides the load into separate 10 Gb/s channels. 

For instance, the 40G channel necessitates 8 fibers, while the 100G channel requires 20 fibers, making the MTP/MPO 12 fiber connector a vital component.

Below is an illustration of how the fibers are utilized in a 40G channel

Below is an illustration of how the fibers are utilized in a 100G channel

Additionally, the 40 Gb/s Small form-factor, hot-pluggable QSFP module plays a pivotal role in distributing the data load across multiple fibers, leveraging the MTP/MPO connector and ribbon fiber assembly. This module adheres to the Small Form-Factor (SFF-8436) standard and comprises independent transmitter (Tx) and receiver (Rx) sections, each featuring four fibers in parallel. Powered by Parallel Optics Technology, it supports MPO-based multimode fiber interconnects and offers a transmission distance of up to 150m over OM3 MMF.

40 Gb/s Small form-factor, hot pluggable QSFP module

This module is designed to split up the data load among multiple fibers utilizing an MTP / MPO connector and ribbon fiber assembly

For reference:

• OM3 cable can carry 10GbE up to 300 meters.

• OM4 cable can carry 10GbE up to 550 meters.

Installing 

Concerning field installations of MTP/MPO cable assemblies for 40 Gb/s and 100 Gb/s Ethernet, there are primarily three methods:

There are basically only three ways of doing field Installations of MTP / MPO cable assemblies:

1. Installation of Factory Pre-Terminated MTP/MPO assemblies, which is recommended due to the relatively new and intricate technology.

2. Fusion splicing Factory Pre-Terminated MTP/MPO pigtail ends onto pre-installed 12-strand ribbon fiber.

3. Installation of -Epoxy/No-Polish MTP/MPO connectors, with currently only one manufacturer offering a field-installable 12-fiber MTP/MPO connector. Given the complexity of this relatively new technology, a cautious "wait and see" approach is advisable. Notably, even most fiber cable assembly houses do not produce MTP/MPO assemblies due to their complexity.

Factory Pre-Terminated MTP/MPO assemblies can be customized in terms of length and equipped with pulling socks and pulling eyes on each end. Their design, featuring one or occasionally two heads on each end, enhances their resilience to forces encountered during cable pulling. While three other field termination methods exist, using Factory Pre-Terminated MTP/MPO assemblies is a prudent choice.

NOTE: It is also noteworthy to mention that due to their complexity, even most fiber cable assembly houses do not make MTP / MPO Assemblies. 

Although there are three other field termination methods available, it is advisable to use only Factory Pre-Terminated MTP / MPO assemblies.  

Conclusion

If you delve into the discussions surrounding "No-Epoxy/No-Polish" connectors, you'll likely encounter claims that they can match the performance of any other system, including fusion splicing. However, this narrative doesn't provide the full picture. 

The reality is that while these connectors are indeed highly effective, like most technologies, they come with their own set of trade-offs and limitations, a characteristic shared by nearly all systems.

Yet, if you prioritize uncompromising performance, especially in the context of Singlemode applications where factors such as back reflection (or the absence thereof) play a significant role in field terminations, your optimal choices narrow down to three options: 

1) Fusion Splice Pig Tails, 

2) Fusion Splice Connectors

3) Factory Pre-Terminated Assemblies.

Specifically concerning the utilization of MTP/MPO Cable Assemblies for 40G and 100G, there are only two secure alternatives: Factory Pre-Terminated and Fusion Splice MTP/MPO pigtails. In this competitive arena, Factory Pre-Terminated MTP/MPO assemblies emerge as the clear victors.

The day someone invents a machine capable of effortlessly loading connectors, inserting fibers, and delivering a flawlessly terminated fiber end with the push of a button, it's certain that copper will face an irreversible decline.