An introduction to fusion splicers.

They are really optical fiber splicers, “fusion” was coined early on to point out optical fibers are glass and a HV arc was required to melt, push together and “fuse” fiber into a single strand.

Early machines were huge with mechanical microscope viewers and needed a name as impressive as the price tag. In the early days there were no agreed standards for fiber manufacture so fusion splicer design moved from v-groove static designs, to more expensive “LID” (light injected), profile (fiber core edge), and core alignment versions – at one point we were paying as much as $20k per machine to “ensure” cores were aligned!

Odd how ribbon machine have alway been and will always be v-groove design and somehow produce “acceptable” loss results of .00 to .03 dB.

Since the turn of the century (17 years ago), manufacturing standards have been established and bulk fibers are pretty much uniform and all the extra gearing, calculation and views are pretty much a carry over mythical requirement. With a skilled cleaver and crimper, a mechanical splice will net you an average .3 to .7 dB loss when joining a fiber. With smaller, faster V-groove designs, and bigger core alignment machines, splices are easily 10 times better at .01 to .03 dB losses. This loss reduction is what installers and their clients are purchasing to reduce their loss budgets.

Did you know with the today’s typical MFD (core diameter) specification for single mode fiber at 9.2 ± 0.4 μm at 1310nm, even at the opposite extremes of this spec, losses due to core mismatch could only be as “large” as ≤ 0.033 dB?

Yet the core-alignment myth continues among non-real world installers. I had one manufacturer justify the need for core alignment in this decade with, “yeah, but if you combine a worst case MFD issue with a maximum core offset it would result in consistent 0.056 dB losses.” I think it would be more prudent to change bulk fiber vendors on the next job.

A couple fiber splicing best practices

No matter the make or model of your splicer, environment is the enemy.  Keep the “automatic” in your automatic fusion splicer with these key tips:

Keep the hood closed between splices.

When placing fiber in the v-groove always center the prepped end between the electrodes and draw back the fiber half way (rather than push forward) before clamping, this action keeps the grooves free of debris rather than lodging it deeper. Remember, “Draw Back, don’t push.”

Persistent out of focus errors? Remove fibers, power off and power back on. Use the  manual splicing mode to align your fibers – your machine always remembers the last settings which is terrific until you inadvertently mislay a fiber and hit set.

Before turning off an automatic fusion splicer, close the hood and hit reset.

Strippers are designed to be used at the same angle as its blade – scrape at a 45 degree angle instead of a “natural” 90 degree angle for a clean strip every time: