How DO you fix a fiber optic line, anyway?

It's not just a matter of plugging the wire back in.

Photographs by Minesh Bacrania

Boomtown photographer Minesh Bacrania got a behind-the-scenes look at repairing the severed fiber optic line that serves as Los Alamos County’s primary information artery. (A link to Boomtown’s full story on the incident is at the bottom of this post.)

On March 17, contractors working on a waterline project on NM 4 severed, for a second time in less than a week, the fiber optic cable that handles nearly all of the communications traffic for Los Alamos County.

Construction drawings for the project indicate the position of the new waterline (shown as “16 W”) being installed. The existing fiber optic line (marked upside down as “FOT”, above the “16 W”) is shown as being between the new waterline and the existing roadway fence.

Wagner Construction superintendent Derek Grieger points out a “Fiber Optic Cable” marking sign, showing the expected location of the cable run next to the roadway fence (left). The true location of the cable run can be seen in the center right of the photograph.

Workers preparing a new section of new fiber optic cable, which had to be ordered and delivered from Albuquerque. The actual splicing operation takes place in the CenturyLink repair van.

Inside the repair van, disassembly of the the severed line is a delicate and tedious process. The original cable was manufactured in the early 1980’s, and consists of 14 individual fiber optic strands bound into a bundle with multiple protective layers.

Each fragile glass fiber strand in the line must be separated, cleaned, and spliced by hand.

The individual glass strands in modern fiber optic bundles are robust and organized using a standard color-coding scheme. The original line, however, is neither.

Each of the 14 fiber strands in the original cable is spliced to the new cable by hand, using a machine that aligns and heats the joint to fuse the glass fiber. The splice is then encased in heat-shrink tubing. The fragile nature of the 1980’s fiber strands means that multiple attempts are often required to achieve a successful splice.

The new and old cables laid out in a purpose-made tray. The heat-shrunk packages of 12 of the 14 spliced fiber joints are held in the center brackets, and the excess length of fiber strands are wound around the perimeter of the tray.

After the splicing is complete, the entire tray is secured in a sealed enclosure.

The enclosure with the repair will be buried in a pre-cast below-grade vault and marked.

Read the full story on this incident here:

Disconnect déjà vu: Los Alamos hit with second blackout in a week