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TECHNOLOGY
Figure 2: With overlay capability enabled, a PON ONT can be added to support additional capacity where subscribers, residential and commercial, require it.
more productive and can reduce time to
market while speeding up the subscriber
connection process.
Established technologies such as
EPON and GPON have gravitated to
common distance, attenuation and split
ratio specifications as well as the use
of a single fiber to reach the premises.
RFOG follows the same basic guidelines
so that an operator building to these
guidelines can operate a wide range of
access technologies over this single design
approach.
Putting It All Together
What does this mean for the system
operator Because the needs of commercial
and residential customers vary and
because each operator’s competitive environment
is unique, it can be expected
that operators will deploy multiple technologies
in the same system. To make
network design, deployment and management
as simple as possible, it is highly
beneficial that just one solution set is
needed for the passive components. This
streamlines the process for engineering
and construction, thereby minimizing
design and deployment cycle times,
lessening crew training requirements
and reducing the inventory of parts that
must be ordered and/or stocked.
Deployment based on standard requirements
also means that changes in
technology are far easier to incorporate.
For example, if increases in commercial
bandwidth demand require migration to
10GePON, this migration can be easily
accomplished by changing or adding to
the devices on the end of the network,
with little or no change to the transport
and distribution cables, splitters, terminals
and drop cables already in place.
During RFOG specification development,
careful attention has been given
to wavelength selection. For cable operators,
1550 nm is a commonly used forward
wavelength, so it is used that way
in RFOG. For the return, consideration
has been given to include a return wavelength
that does not conflict with the
wavelengths used in EPON, 10GePON
and GPON. This makes it possible for
operators to operate both technologies on
the same fiber. RFOG, as a stand-alone
solution, with its familiar use of RF technology
to deliver voice, video and data
services, will be exactly what many subscribers
need. For subscribers needing
more capacity, an overlay with a second
technology provides the extra bandwidth
to support a higher service tier. In some
cases, such as bringing video to the waiting
area of a medical office that already
has voice and data service, RFOG may
actually be the second technology.
The bottom line on RFOG It offers
value to both cable operators and property
owners/developers. Owners and developers
gain through increased property
values in a market where differentiation
is key to maximizing revenues. Cable
operators benefit by having the tools to
capture new business now, and by having
the bandwidth capacity of optical fiber
in the long run. All-fiber access with
RFOG is just another step in how cable
operators can evolve their networks. For
owners and developers, it is another step
in evolving the neighborhood and having
greater choice in all-fiber telecommunications
providers for their projects. BBP
About the Author
Mark Conner is Market Development
Manager, Advanced Access, Corning Cable
Systems, and Shawn Esser is Senior
Product Manager, Access, Optical Transport,
Motorola. Both of them serve on the
committee of the Society of Cable Telecommunications
Engineers that is developing
standards for RFOG. You can reach
Mark at Mark.Conner@corning.com and
Shawn at sesser@motorola.com.
62 | BROADBAND PROPERTIES | www.broadbandproperties.com | January/February 2009