Fiber Splicing technology explained.

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Fiber Splicing, why do we need it?

Fiber Splicing technology is used to precisely align two fiber ends together. Electrodes are used to “fuse” or “weld”  the glass ends together. Afterwards this splice or joint produces a permanent connection between the two fibers. This allows an optical light signal to pass from one fiber to the other with minimal loss. Fiber Splicing is achieved when using a fusion splicer or when using a mechanical splice.

We have discussed mechanical splices in a previous tech talk.

Fiber Splicing machines or Fusion Splicers are known to generate very low losses of typically less than 0.02dB. Such small losses will have little impact on the overall links performance.

Fiber Splicing preparation, what we need to do!

Before optical fiber’s can be successfully fusion-spliced, they need to be stripped and prepared. This involves the stripping of their outer jackets and polymer coating then thoroughly cleaning with lint-free wipes and Isopropyl Alcohol, and then using a cleave tool to precisely cleave a perpendicular end face.

Do not use medical alcohol because it’s mostly water, which can harm the fiber.

Once all of this has been completed, each fiber is placed into a fiber splicing clamp. These carefully engineered fiber splicing clamps allow the precise fixing of the fiber ends. Fiber Splicing from this point on will be fully automatic and the splicer will take over the rest of the process, which typically involves 3 steps:

– Alignment

– Impurity Burn – Off

– Fusion

Fiber Splicing Alignment:

The small precision motors used in fiber splicing make continual adjustments to the fibers’ positions until they’re properly aligned, so the finished splice will be as seamless and attenuation-free as possible, whilst a microscope checks the quality and alignment of the fiber ends.

The Yamasaki Y90 splicer allows you to change the alignment options as follows:-

Align Option

The options to choose from are Fine – Clad – Core.

Fine – The fiber is aligned according to the fiber core and clad

            position. Generally, this is the most precise but takes longer.

Clad – The fiber is aligned to the fiber Cladding

Core – The fiber is aligned to the fiber Core

As can be seen the fiber cores can be viewed from different axis as well:-

Fiber Splicing factors that can affect the “Quality” of your splice.

A high-quality fusion splice is measured by two parameters:

1) splice loss; and

2) tensile strength

Splice Loss Factors

There are two main reasons for loss in any fiber-joining method intrinsic and extrinsic.

Basically, Intrinsic loss factors are determined when the fiber is manufactured and are beyond your control.

For graded-index multimode fibers, the fiber related factors include:-

  • numerical aperture (NA) mismatch,
  • core diameter mismatch
  • diameter mismatch,
  • and core/cladding concentricity

Fiber Splicing Splice loss attributed to core/cladding concentricity can be reduced by splicing the fiber core to core

Extrinsic, or splice process-related, factors are those induced by the splicing methods and procedures.

-include lateral and angular misalignment,

-contamination and

-core deformation.

They can be controlled or minimized by the skill of the individual doing the splicing, and by the automated fiber alignment options:- Fine – Core – Clad

Tensile Strength

The Yamasaki Y90 Fusion Splicer incorporates a pre-programmed pull test after the fiber is fused. If the fiber doesn’t break, it passes the test.

Tensile strength testing is an important technique and should be used as a standard practice. It will assist you in ensuring the robustness and long-term reliability of an optical fiber fusion splice. The default is “OFF” and should always be changed to “ON”. The Yamasaki Y90 tension test = 2N

Important parts of a Fusion Splicer:-

  1. Optical Core or Profile Alignment Systems

The Optical Core Alignment System, also known as PAS, helps in aligning the fiber optic cables at a particular gradient. It is set at 90 degrees once the fiber optic cables are sufficiently illuminated. The PAS uses video camera surveillance to recognize the core of the fibers that could be used for fusion splicing.

  1. PAS Software

The automatic alignment of the PAS fusion splicing module is installed with updated software that helps in estimation of the splicing loss. The PAS software keeps the loss of material and energy to a minimum.

  1. Automatic Fiber Alignment Panel.

Equally important is that while the splicing is being carried out, the fiber optic cables are continuously on the move. After that, the automatic fiber alignment system aligns the fiber optic cables exactly at places where the splicing is to be done.


Above all, Fiber Splicing is a dynamic technique which needs to be extremely accurate. Fusion Splicer are made with precise technology, software and hardware to enable the user to have consistent results in the easiest possible manner. This  brings it home as to how extremely accurate these machines are.