Why should I calibrate fiber optic test and splicing equipment?

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Would
you drive a car with a speedometer that gives you faulty readings? How can you
tell how fast you were driving? Optical testing
equipment that is out of calibration will also cause faulty test
readings. A fusion splicer that is out of calibration will produce inferior
splices. False readings from an OTDR and a poor connector splice joining cable
will cost you time and money. Not to mention customers and network owners who
would question your fiber optic installation work. How do you expect to evaluate
your installation or repair with equipment that has not been calibrated?

 

As
demand keeps growing, more and more of today’s fiber optic network owners are
demanding that their networks handle the increased speed needed to keep up with
those demands. This means that your splice equipment and cleaver need to be up
to the job. With this increased need for speed, today’s loss budgets are lower
than ever. These budgets need to be met. Test equipment must be more accurate
than ever.

 

Items
that need to be calibrated

 

You
need to remember your OTDR is an important piece of diagnostic equipment. It
must be calibrated at specific intervals to ensure correct diagnostics. A power
meter & light source is another important piece of testing equipment in
your arsenal. This tool consists of transmitter and receiver. It measures the
power of an optical signal that is passed through the fiber cable. When two
ends of optical fiber are permanently welded together by an electrical arc,
this is known as a fusion splice. Arc calibration is a must for the proper
splice to take place. Do not forget the optical fiber cleaver. Cleaving is the
process of breaking or cutting of the fiber. A fusion splice requires the use
of a highly accurate cleaver. As you can see the each piece of equipment
mentioned has a specific job. Not calibrating a cleaver or a fusion splicer can
mean a poor splice. Without calibration, optic test equipment such as the OTDR
and power meter & light source are somewhat useless in determining things
like the quality of connectors and splices.

 

What
is a loss budget?

 

This
calculation is the total optical power loss that the system is allowed to have.
This amount is determined by the power losses resulting from the total amount
of equipment that the system has. A loss budget for fiber optic networks is
derived from installation of items such as patch cords; couplers, adaptors,
splices, cable and any additional optical components installed in the system.
This is determined when the network is designed. After it is installed this
loss must be tested to see if the budget has been met. Is the splice that has
been made to extend the cable acceptable? How about a connector? Was it
installed properly? Another equally important reason for OTDR testing, is once
the system is active, later on if a problem presents itself, you can go back to
the original test. You could then compare the new test to the original test and
determine the problem quickly and easily. This is why accurate OTDR testing
equipment must be maintained. In order for that piece of equipment to be
accurate it must be calibrated on a regular basis.

 

Calibration
is not an option. It is a must.

 

Put
calibration off and it could cost you more than the cost of the calibration
itself. Incorrect readings could have technicians thinking the installation is
better than it really is or just the opposite. Your company name depends on
quality and accuracy. It is not worth saving a few bucks on calibration. During
the year your equipment such as splicing equipment is subjected to all sorts of
events that can cause it to go out of calibration. If you are in the south heat
can be your enemy. Up north freezing temperatures are not your friend. Have you
left your equipment in your truck only to be bounced around? All those bumps,
drops and bangs add up to inaccurate readings. Dirty conditions are no help
either. In many instances in order to get paid you need up to date certified
testing equipment. If you are certified for ISO 9001 you need your equipment
calibrated. ISO clause 7/6 reads in part as; Control of monitoring and
measuring equipment. The organization shall determine the monitoring and
measurement to be undertaken and the monitoring and measuring equipment needed
to provide evidence of conformity of product to determined requirements. The
organization shall establish processes to ensure that monitoring and
measurement can be carried out and are carried out in a manner that is
consistent with the monitoring and measurement requirements. Remember,
calibration is always a must when the measurements from your equipment are
critical – It’s that simple.

 

What
exactly is calibration?

 

When
you calibrate any piece of equipment the unit to be calibrated is compared to a
unit of a known value. This known value comes from another similar device of
known accuracy and precision. Equipment that has a laser which is being
calibrated means that laser must fall within a specific acceptable range.
Should the equipment being tested be found to be “out of calibration” and
produces faulty readings, the equipment must be repaired or adjusted so it
falls within the acceptable specified range of measurement.

 

What
is NIST Calibration?

 

NIST
stands for National Institute of Standards and Technology. They provide
services to make sure the equipment being calibrated is measured up to a
particular piece of equipment similar to that of the equipment being
calibrated. NIST certifies that that the lab testing to equipment uses a method
that meets the standards of the NIST and must match the NIST measurement standard
for a particular piece of equipment. For fiber optic purposes, that would be
equipment such as an OTDR, a fusion splicer, cleavers, power meters and lights
sources.

 

In
simple terms when using the NIST method you need an unbroken chain of
documents; your piece of equipment and components are compared to our piece of
equipment which in turn was compared to a piece of equipment from the NIST
which is within a stated tolerance. NIST sets the tolerance and it is correct.
Our equipment was compared to the NIST equipment so we know ours is correct.
Finally yours is compared to ours and found to be correct. That is an unbroken
chain. This unbroken chain which is traced back to NIST standards for accurate
measurement is how uniformity is maintained. Once your equipment has been
tested and meets NIST standards you will receive a calibration certificate
paper work stating the results and the date. This means your equipment has met
the highest test standards. A big plus would be getting that certification from
an ISO compliant calibration company.

 

What
is ISO?

 

The
International Organization for Standardization (ISO) is the world’s largest
non-governmental organization developer of standards. ISO 9001 is the most
sought-after and internationally acclaimed management system standard. They
have created over 22,808 International standards and goals. Their standards are
voluntary. Companies who seek out this standard are ensuring that their
customer requirements are met accurately and consistently. When it comes to
calibration a company is working to meet a set of regulatory requirements which
in turn will improve company performance, which will improve product and
service quality. This method in the end will benefit the customer by assuring
them that the ISO certified company has met the exacting ISO standards to bring
them a better product.

 

Conclusion

 

Over
time even a well cared for piece of test equipment can lose its’ accuracy. You
must have your equipment calibrated as suggested by the manufacturer. However,
in many instances you may need to get it done sooner, as many conditions that
the equipment is subjected to may alter or falsify your test results. As
networks need to increase their efficiencies loss budgets are becoming smaller
and smaller. Only calibrated equipment can assure you are correctly within that
budget. Calibration is not really an option. It is a must. Always use a lab
that will test to NIST standards and if possible use an ISO certified test lab.
Accurate results will always save you time, money and your company reputation.