- Automated Pigtail Fabrication Needed for Future Networks
The "process-centric" automation of fiber pigtail fabrication is a step toward a revolution in fiber optics manufacturing for next-generation networks.
Dr. William L. Emkey
The need to automate the manufacture
of fiber optic components is clear. Automation must be embraced if the industry
is to fuel the expansion and urban deployment of next-generation networks. The question
is how best to implement automation in the manufacture of fiber optics.
Most attempts to date have featured fragmented,
single-process automated or semiautomated manufacturing cells that still require
extensive manual participation. These “person-centric” approaches, while
an improvement on purely manual assembly, fall short in terms of product quality,
consistency and cost.
Automating the fiber pigtail fabrication process improves the assembly of fiber optic components by eliminating
the problems associated with human intervention. KSaria Corp.’s Prima automated
fiber pigtail fabrication system features a throughput of 120 fibers per hour.
True automation is best achieved using
a “process-centric” approach that examines each step to determine a
way to automate it, with the goal of removing human subjectivity from the system
and of establishing measurable parameters for each step of the assembly process.
The result is a seamless, in-line system that achieves consistent, repeatable results
and lowers manufacturing costs by increasing first-pass yield and throughput.
Until recently, automation of pigtail
fabrication had not been considered feasible. Today, however, an automated in-line
system can produce a pigtail with no operator intervention. A key component is the
fiber work tray, which facilitates movement throughout the automated processes and
enables the transportation of processed fiber without touching it. A well-designed
fiber work tray:
A well-designed fiber work
tray is a key element of automated fiber pigtail fabrication. The tray eases the
movement of the fiber through the process and enables the operator to transport
the fiber without touching it.
• Never violates the minimum
bend radius of the fiber.
• Facilitates the loading and
unloading of fiber.
• Includes strain relief to protect
• Includes retention mechanisms
for fiber coils and ends that hold fiber in place in various positions.
• Withstands the harsh chemicals
and high temperatures of a manufacturing environment.
• Eliminates electrostatic buildup.
• Includes registration features
for the automated identification of the fiber position.
• Adapts to accommodate various
ferrules and end shapes.
• Is stackable for volume handling
Preparation and termination
The production of high-quality, high-yield fiber
optic components begins with pigtail fabrication, which can be divided into two
processing steps: fiber preparation and fiber termination.
Until recently, it was
not feasible to automate pigtail fabrication. The process can be divided into two
steps: fiber preparation and fiber termination. Preparation consists of dispensing
a specific length of fiber onto the work tray and stripping and cleaning the fiber.
Termination consists of cleaving the fiber, attaching the ferrule (which involves
alignment, fiber insertion and the application and curing of the epoxy) and polishing
the surface. Images courtesy of kSaria Corp.
Fiber preparation consists of spooling,
stripping and cleaning, each of which must be done consistently and precisely at
the start of assembly. The in-line process begins by inserting a cassette of stacked
work trays into the system’s tray management module, which loads the trays
onto a self-aligning transport mechanism that moves each to the payout and spool
tool. The tool extracts a programmed length of fiber from the fiber reel and spools
it onto the work tray without violating the minimum bend radius. This is difficult
to do by hand and often results in fiber damage that may not be detected until much
later in the manufacturing process.
The fiber work tray is then indexed
to the stripping tool, where a programmed length of buffer is heated and stripped
from the end of the fiber. Automatic stripping has several advantages over manual
or benchtop stripping, including the use of controlled and optimized temperature
profiles, a more reliable and consistent strip because of the automatic blade positioning,
and consistent fiber strip lengths and pull strengths.
Next, the tray is indexed to the cleaning
tool, where the fiber is ultrasonically cleaned with a nonalcoholic, noncombustible
fluid. The automatic tool provides a rapid cleaning process that results in a consistently
After preparation, the ends of the
fibers must be terminated. Depending on the application, the fiber cleave operation
can be the final termination step, or it can be the step prior to inserting the
end into a ferrule. In the latter case, cleaving reduces the possibility of axial
crack propagation during subsequent handling, and it facilitates insertion into
This operation has several physical
characteristics that must be controlled, including cleave angle, fiber hackle and
fiber chipping. In automated cleaving, the tray moves to the tool, which cleaves
the fiber to meet or exceed industry standards. Because this process is done automatically
with the associated monitoring and control, it achieves extremely consistent cleave
angles and better cleave quality than manual or manually assisted processes.
The tray moves on to the ferrule or
capillary attach module. At this point, the system must accommodate a variety of
ferrule termination options, including ferrule geometries, orientations, materials,
epoxy-bonding requirements and buffer distances. Automatic, in-line attachment provides
the flexibility and precision control throughout the process to address these options.
Automation offers the necessary precision alignment, fiber insertion, bubble-free
epoxy application and curing control for consistent ferrule attachment, which is
almost impossible to achieve with manually assisted operations.
In the final step, the tray moves to
the polishing module to undergo a controlled sequence of polishing operations for
a premium surface finish. The polishing station can be programmed to provide a variety
of end-face finishes, including normal planar, angled planar and spherical.
The completed assembly is then cleaned,
and the tray is indexed to an inspection stage where a vision system determines
whether the end face meets polish quality specifications. Rejected pigtails can
be recycled through the system for repolishing or removed for disposal. Finished
pigtails are loaded into a cassette for the next process.
A fully cued system, beginning with
the fiber on a spool, provides one terminated fiber pigtail per minute.
The automation of the fiber pigtail fabrication
process clearly improves the assembly of fiber optic components, eliminating the
problems associated with human intervention. It is a flexible, hands-off, process-centric
solution that yields high-quality fiber pigtails quickly and cost-effectively with
consistent, repeatable results.
Manufacturers have long recognized
that manual and semiautomated methods do not meet the demands of broadband network
deployment and that they will limit industry growth and profitability. This is particularly
evident in the manufacture of optical components and modules, which make up the
core of the sophisticated, next-generation networks — especially those poised
for metropolitan deployment. Fiber optics manufacturers must produce components
with higher quality and consistency at lower costs to meet future demand and to
thrive as an industry.
Automation — full, in-line, process-centric
automation — is the solution. It will solve both the cost and quality issues
that plague the industry. It represents not an incremental change to current processing
methodologies, but a huge first step toward a true revolution in fiber optics manufacturing.
Meet the author
William L. Emkey is chief technology officer at
kSaria Corp. in Wilmington, Mass. Prior to joining kSaria, he was an associate professor
of physics at Pennsylvania State University, managed optical design and development
teams at Lucent Technologies Inc.’s Bell Labs in Murray Hill, N.J., and was
vice president of product marketing at Lightchip Inc. in Salem, N.H. He holds seven
patents on devices such as optical couplers and isolators, and has a PhD in solid-state
physics from Lehigh University.
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