Passive WDM transport means can be used to set-up multiple, up to 24, 100Gbps services in the same way that passive DWDM 10Gbps networks have been used to augment capacity in metro environments. And similar to passive 10G WDM networks, passive 100G DWDM networks are installed at a fraction of the cost of the active transport counterparts.
Similar to the LR4 versions featuring 4 lasers and 4 detectors (each at 25Gbp, each at specific lambdas), the heart of passive 100Gbps DWDM solutions are 100Gbps DWDM CFP MSA compliant transceivers - they only come without the optical WDM multiplexer integrated into the transceiver. This requires an external (e.g. 19" based, passive DWDM) multiplexer.
In contrast to CFP LR4 types, the CFP DWDM versions are based on tunable lasers (50GHz DWDM grid) in the 1550nm spectrum.
A set of up to 24 "differently colored" 100Gbps DWDM can be transported via a 96 channel passive DWDM mux (each CFP uses 4 lambdas) in parallel over a single-mode fiber pair.
As with 10Gbps DWDM networks, those signals can be reach-extended by the use of standard EDFA (Erbium Doped Fiber Amplifier) amplifiers. This enables the transport of up to 2.4 Tbps in a passive WDM manner without additional and costly amplifiers over distances of hundred and more km's