Техническая Спецификация для Cisco Cisco Prisma iWDM Passives
Description
To handle increasing bandwidth requirements cable operators are
being forced to upgrade their network architectures. These changes
are pushing optical fiber deeper into the network. But simply
replacing existing transmission lines with fiber is no longer the most
cost-effective means to expand bandwidth. Improvements in optical
filtering are making it possible to significantly increase the number of
wavelengths in a single fiber. CWDM (Coarse Wavelength Division
Multiplexing) has gained prominence in multi-wavelength digital
transport architectures because it permits the use of low-cost,
un-cooled DFB laser transmitters. Moreover, powering
requirements are reduced and reliability is increased compared with
DWDM solutions.
This suite of CWDM passives is specifically designed to meet the
requirements of HFC architectures. The CWDM laser is located in the optical node, which is typically placed
in an outdoor environment with relatively high temperature changes. These temperature variations place
special restrictions on the channel bandwidth in the CWDM passives. The analog nature of the signals
transmitted through the HFC network also necessitates a tighter control of the specifications of the CWDM
passives compared to those designed for digital transmission systems.
Scientific-Atlanta’s 16-Channel CWDM system is optimized for the analog transmission in HFC networks. It
also provides a very powerful solution for fiber-poor areas, and a cost-efficient alternative to DWDM for short
to medium distances. CWDM differs from Dense Wavelength-Division Multiplexing (DWDM) in that the optical
channel spacing between the light sources is much greater (20 nm). This wide spacing, combined with a tight
control of the channel boundaries in the CWDM passives, means that variations in the wavelength of reverse
transmitters due to temperature changes will not result in loss of signal/service. This in turn allows the use of
un-cooled DFB lasers and therefore drives down the costs and power consumption significantly while
increasing overall reliability.
being forced to upgrade their network architectures. These changes
are pushing optical fiber deeper into the network. But simply
replacing existing transmission lines with fiber is no longer the most
cost-effective means to expand bandwidth. Improvements in optical
filtering are making it possible to significantly increase the number of
wavelengths in a single fiber. CWDM (Coarse Wavelength Division
Multiplexing) has gained prominence in multi-wavelength digital
transport architectures because it permits the use of low-cost,
un-cooled DFB laser transmitters. Moreover, powering
requirements are reduced and reliability is increased compared with
DWDM solutions.
This suite of CWDM passives is specifically designed to meet the
requirements of HFC architectures. The CWDM laser is located in the optical node, which is typically placed
in an outdoor environment with relatively high temperature changes. These temperature variations place
special restrictions on the channel bandwidth in the CWDM passives. The analog nature of the signals
transmitted through the HFC network also necessitates a tighter control of the specifications of the CWDM
passives compared to those designed for digital transmission systems.
Scientific-Atlanta’s 16-Channel CWDM system is optimized for the analog transmission in HFC networks. It
also provides a very powerful solution for fiber-poor areas, and a cost-efficient alternative to DWDM for short
to medium distances. CWDM differs from Dense Wavelength-Division Multiplexing (DWDM) in that the optical
channel spacing between the light sources is much greater (20 nm). This wide spacing, combined with a tight
control of the channel boundaries in the CWDM passives, means that variations in the wavelength of reverse
transmitters due to temperature changes will not result in loss of signal/service. This in turn allows the use of
un-cooled DFB lasers and therefore drives down the costs and power consumption significantly while
increasing overall reliability.
The CWDM Multiplexer/Demultiplexer (MUX/DEMUX) is an essential component for implementing CWDM to
increase network efficiency by significantly reducing fiber counts. The unit is available in the industry
recognized, LGX-compatible form factor to allow easy, snap-in mounting in a variety of enclosures and
cabinets. The LGX module can be used in the same chassis as coupler/splitters and patching modules to
achieve high-density rack configurations. The MUX/DMUX component is also optimized to reduce combined
insertion loss at all wavelengths.
increase network efficiency by significantly reducing fiber counts. The unit is available in the industry
recognized, LGX-compatible form factor to allow easy, snap-in mounting in a variety of enclosures and
cabinets. The LGX module can be used in the same chassis as coupler/splitters and patching modules to
achieve high-density rack configurations. The MUX/DMUX component is also optimized to reduce combined
insertion loss at all wavelengths.
Features
•
Enables up to 16-fold capacity increase in the reverse path over single wavelength solutions
•
Specifically designed for HFC node applications
•
Universal MUX/DMUX module available for 4, 8, 12 or 16 channel configurations
•
Channels spaced at 20 nm, following the standard CWDM wavelength grid
•
The CWDM’s wide channel spacing allows the use of un-cooled DFB lasers
•
Wavelength mapping options allow combination of broadcast and reverse services on a single fiber
•
LGX-compatible modules easily snap in to a wide variety of enclosures and cabinets
•
Industry-standard SC/APC or E2108 adapters ensure connector compatibility; minimize back reflection
and insertion losses; simplify moves, adds & changes; and reduce connector maintenance
requirements
and insertion losses; simplify moves, adds & changes; and reduce connector maintenance
requirements
Optical Passive Components
CWDM Passives for
16-Channel CWDM HFC Architectures
16-Channel CWDM HFC Architectures