Test and Measurement for Future Networks
Test and measurement evolves in anticipation of advanced components, emerging protocols
and streamlined network architectures.
It’s no secret that telecommunications carriers are reducing their capital expenditures
because of a more competitive landscape. Consequently, these carriers will not
necessarily deploy new optical networks. However, they will upgrade existing networks
by adding dense wavelength division multiplexing (DWDM) channels, lighting dark
fibers and increasing data transmission rates.
Also, the traditional boundaries defining the
physical, optical and protocol layers of optical networks will blur as DWDM networks
simplify their topology. From a protocol perspective, we foresee hybrid systems
like SONET-Ethernet growing in importance, especially in the metropolitan-access
In coming months, expect to see more hybrid field-testing platforms
capable of testing the physical, optical and protocol layers with a single box.
Photos courtesy of Exfo.
Testing requirements will be influenced
greatly by the emerging implementation of protocol-independent DWDM networks capable
of dynamic bandwidth assignments. A good example of this is enterprise networks,
which are deployed to provide data storage area networks.
These trends will fuel the emergence
of comprehensive physical-, optical- and protocol-layer test equipment for long-haul,
metro and access networks. Already appearing are portable testing platforms that
can operate multiple field-interchangeable modules for high-end DWDM testing, characterization
of polarization mode dispersion, high-fiber-count testing, as well as optical time-domain
reflectometry and optical loss testing. Similarly, performance management equipment
has emerged to support a wide variety of protocols, including asynchronous transfer
mode, SONET, synchronous digital hierarchy, Ethernet, Gigabit Ethernet and data
transmission rates from 64 kb/s to 10 Gb/s.
The progressive hybridization of test
and measurement equipment won’t stop there. Expect to see early this year
field-testing platforms that will enable field technicians to be far more efficient
and cost-effective by seamlessly carrying out physical-, optical- and protocol-layer
tests with a single box in their hands.
On the optical component and system
manufacturing side, the slowdown in network deployment and the resulting buildup
of inventories have directly affected vendors. Leading manufacturers, however, cannot
afford to curb spending on research and development in their quest to design next-generation
solutions that will keep them one step ahead of the competition. As a consequence,
new production lines of increasingly complex optical components — such as
arrayed waveguides, optical hybrids and integrated optics — will be required.
These components require fast-measurement test stations to provide positioning feedback
for fiber termination on the devices.
Slowing network deployments won’t stem the research and development
that keeps manufacturers ahead of their competition. Hence, test and measurement
will help development of next-generation arrayed waveguides, optical hybrids and
Furthermore, the trend toward 40-Gb/s
systems is no longer a matter of if but when. Whatever the time line, 40-Gb/s data
rates will place enormous pressure on manufacturers to find highly accurate and
quick instruments for measuring polarization mode dispersion in the femtosecond
range. Measurements must be obtained in femtoseconds because even the smallest
effects of polarization mode dispersion from individual components have a cumulative
effect on the overall performance of high-speed optical networks.
We’re already beginning to see
analyzers that enable simple, fast and repeatable measurements of very small dispersion
effects in narrowband DWDM channels and broadband components.
Chromatic dispersion is another limiting
factor. As a result, we can expect new generations of test equipment to measure
this physical phenomenon on deployed networks and individual components.
Besides more sophisticated instruments
for 40-Gb/s testing, users are demanding instrumentation with greater ease of use
and shorter testing cycles. Vendors will continue to introduce simplified, single-button
automated test systems that enable nonexperts to characterize complex optical parameters
in less than a minute on the production floor.
In summary, the increasingly competitive
environment is driving telecommunications carriers as well as optical component
and system manufacturers to extract the greatest possible value from existing optical
networks through enhanced solutions. The challenge for test and measurement vendors
is to support these customers in their quest to develop next-generation solutions
with innovative products that are highly accurate, are fully reliable and that,
by design, save time.
Meet the author
Mario Larose is responsible for marketing and
customer service activities at Exfo. He holds a bachelor’s degree in engineering
physics from École Polytechnique in Montreal and an MBA from the Université
du Québec à Montréal.
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