FOA Lecture 5: Splices and Connectors

Summary

This lecture, part of a fiber optics series by The Fiber Optic Association, covers fiber optic splices and connectors, highlighting their differences and applications. Splices are permanent connections typically used in outdoor settings, while connectors allow for demountable fiber terminations. The video discusses the importance of low loss, reflectance, and high mechanical strength for both splices and connectors. It compares fusion and mechanical splicing methods, their processes, and costs, and emphasizes the evolution of fiber optic connectors over the years. Additionally, the lecture explores the advantages of prefabricated cabling systems for field installations.

Takeaways

• 😀 Fiber optic splices and connectors are methods for joining optical fibers, with splices being permanent and connectors providing demountable terminations.
• 😀 Splices are often used for outdoor plant fiber connections, while connectors are ideal for testing and connections to active devices.
• 😀 Both splices and connectors must meet high standards for low loss, low reflectance, mechanical strength, reliability, ease of installation, and environmental resilience.
• 😀 Loss is a critical factor in fiber optic performance, with potential causes being imperfect connectors, fibers, or processes.
• 😀 Reflectance occurs when air gets between fiber interfaces, which can affect performance, particularly in high-power, high-bit rate systems.
• 😀 There are two main types of splices: fusion splices, which use an electric arc to weld fibers, and mechanical splices, which use alignment sleeves and gel.
• 😀 Fusion splicing typically results in lower loss due to the precise welding process, but requires expensive machines and cleavers.
• 😀 Mechanical splicing is a simpler, less expensive alternative to fusion splicing but tends to cost more per splice due to its complex mechanical components.
• 😀 Completed splices need protection, usually through splice trays and closures, to shield them from environmental factors.
• 😀 Over 80 types of fiber optic connectors have been introduced, with popular ones including ST, SC, LC, and MTP connectors, each evolving to offer smaller sizes and lower losses.
• 😀 Modern fiber optic connectors often use adhesive and polishing techniques for terminations, and prefabricated cabling systems can reduce field work significantly, making them cost-effective for new constructions.

Q & A

What are the main differences between fiber optic splices and connectors?

Splices are used to permanently join two fibers, typically for outdoor applications, while connectors provide demountable terminations for fibers, allowing access for testing and connection to devices like transmitters and receivers.

What performance characteristics are required for both splices and connectors?

Both splices and connectors need to have low loss, low reflectance, high mechanical strength, high reliability, ease of installation in the field, and the ability to withstand environmental conditions.

Why is loss such an important specification when joining optical fibers?

Loss is crucial because it directly impacts the efficiency of the fiber optic system. Loss can occur due to imperfect connectors, fibers, or processes, and understanding these factors is essential for minimizing the loss when fibers are joined.

What causes reflectance in fiber optic splices, and why is it a problem?

Reflectance occurs when there is air in the interface between two fibers, causing reflections that can interfere with lasers or introduce noise in high bit-rate, high-powered systems.

How are fusion splices and mechanical splices different?

Fusion splices use an electric arc to weld two fibers together and provide lower splice loss, whereas mechanical splices use an alignment sleeve and index matching gel to hold the fibers in place and tend to be more expensive due to the complexity of the splice device.

What are the steps involved in fusion splicing?

In fusion splicing, you strip, clean, and cleave the fiber, place the fiber in the splicer, repeat the process with the second fiber, start the automated program, and the splicer completes the weld and estimates the loss.

What protection is necessary for splices after they are made?

After splices are completed, they need to be placed in a splice tray, which is then inserted into a splice closure to protect the fibers and splices from the environment.

How have fiber optic connectors evolved over the last 30 years?

Fiber optic connectors have become significantly smaller and lower in loss. Early connectors, like the Deutsch, had much higher loss, while modern connectors like the LC and SC have much lower loss and are about one-tenth the size.

What is the advantage of prefabricated cabling systems in fiber optics?

Prefabricated cabling systems are cost-effective and efficient for new construction, as all the work is done in the factory, and the system requires very little time and effort to install in the field.

What is a typical use case for the MTP multi-fiber connector?

The MTP connector is used in multi-channel systems, especially in prefabricated cable plants, although it is less commonly used than single-fiber connectors.