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Updated:October 6, 2009
The Cisco® 2-Channel SFP WDM Transponder expands the range of applications and platforms supported by coarse wavelength-division multiplexing (CWDM) and dense wavelength-division multiplexing (DWDM) pluggable optics solutions from Cisco. It supports any client, any protocol, and any speed between 155 Mbps (OC-3/STM-1) and 2.488 Gbps (OC-48/STM-16).
The Cisco 2-Channel SFP WDM Transponder (Figure 1) is an unmanaged unit that can be used to convert any incoming optical signal into a CWDM or DWDM channel. Its flexibility in terms of data rates, protocols, and wavelength-division multiplexing (WDM) options is provided by Cisco pluggable optics, which reside on both the client side and the trunk side.
In addition, when Small Form-Factor Pluggable (SFP) devices with the same wavelength reside on client and trunk sides, the unit can be simply used as a 3R regenerator (re-amplification, reshaping and retiming) for the uplink data stream (client to network path) and a 2R regenerator (re-amplification and reshaping) for the downlink data stream (network to client path), turning it into a very dynamic and flexible module.
Figure 1. Cisco 2-Channel SFP WDM Transponder
The transponder effectively extends the range of client devices that can connect to the CWDM or DWDM network using pluggable optics: third-party SONET/SDH add/drop multiplexers (ADMs), storage and Ethernet devices, or Cisco platforms that do not support pluggable WDM optics can connect to the WDM network by using this transponder, which operates the wavelength conversion from older 850/1300/1550 nanometer (nm) signals to any CWDM or DWDM channels. This conversion is enabled by the WDM SFP ports sitting on the line side (Figure 2).
Figure 2. SFP Ports on the Transponder
Each transponder supports up to two CWDM or DWDM line SFP optics (plugged into the ports labeled "NTWK1" and "NTWK2") as well as two client SFP optics (plugged in the ports labeled "EQPT1" and "EQPT2"). The range of Cisco SFP optics on the transponder supports any protocol and speed between 155 Mbps and 2.488 Gbps.
The transponder is compatible with the passive Cisco CWDM chassis (Figure 3) (part number CWDM-CHASSIS-2=). Two transponder devices can coexist together in the two-slot chassis. There is no limit to the number of chassis that can be stacked in a rack. Alternatively, the transponder can coexist in the same chassis with any Cisco CWDM passive filters.
Figure 3. Cisco CWDM Chassis
Table 1 lists the compatible SFP optics required by each application.
Table 1. Supported SFP Optics and Applications
Bit Rate (Mbps)
Client SFP (Product Number)
CWDM Line SFP (Product Number)
DWDM Line SFP (Product Number)
The transponder is designed for situations where most of the equipment operates directly with pluggable optics, but a few platforms without WDM pluggable optics need to connect to the WDM network. Figure 4 shows an example of two sites connected through SONET links: The transponders at each location take the signals from the SONET equipment and convert them to CWDM channels, which communicate with passive Cisco CWDM devices.
Figure 4. Example Deployment Scenario
The Cisco 2-Channel SFP WDM Transponder is an unmanaged unit that runs no software. The front-panel LEDs (Figure 5) report various alarm conditions as summarized in Table 2. Tables 3 to 6 list product and optical specifications.
Full width, -20dB from maximum, with resolution bandwidth (RBW) = 0.01 nm
Transmitter Center Wavelength
λ - 100
λ + 100
Center wavelengths are in-line with Cisco DWDM channel plan and 100GHz ITU grid
Side-Mode Suppression Ratio
Transmitter Extinction Ratio
Transmitter Optical Output Power
Average power coupled into single-mode fiber
Receiver Optical Input Wavelength
Receiver Damage Threshold
Power-Limited Performance at OSNR of 20 dB (< 2000 Mbps) or 21 dB (> 2000 Mbps) at 0.1-nm RBW
Optical Input Power
Dispersion Power Penalty < 2000 Mbps
Dispersion Power Penalty > 2000 Mbps
Noise-Limited Performance at OSNR of 18 dB (< 2000 Mbps) or 19 dB (> 2000 Mbps) at 0.1-nm RBW
Optical Input Power
Dispersion OSNR Penalty < 2000 Mbps
Dispersion OSNR Penalty > 2000 Mbps
To place an order, visit the Cisco ordering homepage. Table 7 lists ordering information for the Cisco 2-Channel SFP WDM Transponder.
Table 7. Ordering Information
Cisco 2-Channel SFP WDM Transponder
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