History / Technical details Tunable DWDM SFP+
There are two Power Levels defined:
- Power Level I modules - up to 1.0 W
- Power Level II modules - up to 1.5W
Very low power consumption compared to XFP MSA which has defined Power Levels up to Level 4 with greater than 3.5 W. Resultant from this low power consumption there is one main difference between tunable XFP and tunable SFP+: CDR functionality. (Clock-Data-Recovery)
XFP is born with CDR (defined in MSA) while SFP+ is without. Sure there are some SFP+ on the market with CDR but these are already working at Power Level II so that there is no space for tuning capability.
Usually the host board for xWDM applications have a CDR chipset or the transceiver is working with a FEC (Foward-Error-Correction) mechanism.