High-Capacity IPoDWDM Networks with 400G ZR and ZR+

Posted by Tim Yanda on Nov 22, 2023

The promise of high-capacity IPoDWDM is occurring. With the commercialization of 400ZR/ZR+, we can build high-capacity circuits in a solid, straightforward system. We can build a robust course using the tunability of 400ZR/ZR+ transceivers and simple passive DWDM mux/demux modules. A four-channel system will carry 1.6 Tbps of traffic over a fiber pair, and an eight-channel system will provide 3.2 Tbps of IP traffic. The distance will vary based on fiber type and selected transceiver options, but unamplified circuits can reach up to 60km.

Transceivers with 4 Channel Mux/Demux:

Transceivers with 8 Channel Mux/Demux:

Transceivers without Mux/Demux:

With Amplification:

With the addition of EDFA amplifiers, this distance can be extended substantially. The 400ZR parts can reach 120km, and 400ZR+ can reach up to hundreds of kilometers. The difference between the two parts is the type of FEC they use.See our article “Fiber Optics of the Near Future: 400ZR and 400ZR+”

As with all high-capacity long-reach circuits, it is highly recommended that the fiber plant is properly characterized.

EDFA amplifiers are low-power draw at 3 to 5 watts of power. Some amplifiers come in pluggable form factors (SFP+ and QSFP) and traditional rack mount units. Several notes of caution/planning: clear understanding of where the amplifier gets placed in the circuit; input composite power; the number of fiber wavelengths (carriers); and future growth (4-channel or 8-channel passive mux/demux and initial or added transceivers.

Engineered Solution:

Several other key factors need to be understood. The 400ZR/ZR+ components' power requirements are up to 22 watts per port. As such, it is critical to know the switch's power and heat dissipation capability. CMIS 5. x is the standard that both the transceiver and switch must be on. Although CMIS 5. x is a standard; there are nuanced differences from switch to switch and among transceiver manufacturers that must be engineered into the solution.

Preliminary Spec — (Subject to Change):

Designing and building these ultra-high-capacity circuits with 400ZR/ZR+ is approaching plug and play, but at this time, it is still an engineered solution that requires proper planning, proper fiber characterization, and well-thought-out configuration of the switches, passives, amplifiers, and future growth.