How to do fusion splicing

What is fiber fusion splicing?

The purpose of fiber fusion splicing is to join two fibers together. In the fusion splicing process a specialized fusion splicer machine is used to precisely align the two fiber ends then the glass ends are "fused" or "welded" together using electric arc or some type of heat. This produces a transparent, non-reflective and continuous connection between the fibers enabling very low loss light transmission. (Typical loss: 0.1 dB)

 

 

What other options are available for fiber splicing?

The other method for joining two fibers is mechanical splicing. Fiber optic mechanical splicing uses a mechanical alignment device called mechanical splices to hold two fiber ends in a precisely aligned position thus enabling light to pass from one fiber into the other. Splicing loss is typically 0.3dB. But fiber mechanical splicing introduces higher reflection than fusion splicing method.

Advantages of fusion splicing

• Lower splicing loss: 0.1dB typical
• Lower cost per splice: $0.5 to $1.5 each
• Less back reflection. The splicing point is almost seamess.
• Best choice for single mode applications

Tools and consumables needed in fiber fusion splicing

Types of fusion splicers

• Full-Featured - Includes machines that are fully automatic, provide extremely low splice losses by aligning the cores of the fibers, and have plenty of special features to make splicing as easy as possible.

• Mass - Includes machines that can splice ribbon fibers from 2-12 fibers. Also splice single fiber.

• Micro - Includes machines that are very portable, yet still maintain many of the features of the full-featured machines. Still fully automatic. Micro splicers typically use Fixed V-groove technology for fiber alignment.

• Manual - Includes machines that are not automatic. Require more user skill, but are the least expensive available.

How does the fusion splicer align the fibers?

Passive Alignment

The splicer uses V-shaped groove to hold the fibers in place along the X and Y axes. The only movement of the fibers is along the Z axis as the splicer brings the fibers together. This process relies heavily on precisely-shaped V-grooves and very clean fiber. Chipped V-grooves or dirty fibers can affect the X or Y alignment to the point that the splicer cannot perform a good splice on them. Passive alignment only allows cladding alignment because the fibers cannot be moved to align the cores.

 

 

Active Alignment

Active alignement aligns on all 3 axes. The splicer still uses a V-groove to hold the fibers in place, but in active alignment it can actually move the V-groove area along the X, Y, and Z axes to bring the fibers into alignment with each other. This 3-axis alignment allows for core alignment instead of just aligning the fibers based on their outside geometry. Due to the expensive electronics and motors required to handle this type of precision movement, this process is only found on high-end machines.

 

 

Fiber fusion splicing process

1. Fusion Splicer Overview

1. Fiber Preparation
2. Inserting the Fibers
3. Select Splicing Program
4. Splicing
5. Heating Fusion Splice Protection Sleeve
6. Troubleshooting