OIF finishes thermal interface spec for pluggable optical transceivers

The Optical Internetworking Forum (OIF) says its members have completed work on a new implementation agreement that covers thermal management of pluggable optical modules.

"When optical modules are mated with heatsinks, the goal is to remove over 90% of the heat through the interface area into the airflow stream via the heatsink," said Torsten Wuth, of Coriant and the OIF Physical Layer User Group Working Group chair. "Nominal ranges of heat flux are defined as Power Density classes. The OIF agreement defines acceptable thermal impedances for the contact area for various pluggable module types and a method of measuring the impedance."

The implementation agreement builds on previous work within the OIF, summarized in a 2012 whitepaper entitled "Thermal Management at the Faceplate" (see "The OIF addresses speed, security, and control plane management"). The whitepaper covers the various ways the heat optical transceivers dissipate can be managed via air-cooling, treating such aspects as the direction of airflow over the modules, internal system baffling to direct airflow, placement of the modules and other heat dissipating devices on the blade, optimization of fin layout on the heatsink, and increasing the heatsink's thermal conductivity. It also discussed the importance of thermal contact resistance between the module and the heatsink.

The new agreement summarizes the information module suppliers should supply to facilitate thermal integration of their modules within a host system. It also defines the requirements and methods for testing the thermal interface between a pluggable optical module and the host-system heatsink.

The agreement is applicable to a wide range of pluggable optical transceivers, including the CFP, CFP2, CFP4, XFP, SFP, SFP+, QSFP, QSFP+, and CDFP. The OIF says that interfaces where the module slides through the faceplate and under a spring-loaded heat sink can be particularly tricky. In this scenario, the interface has limited contact force because the insertion and extraction force and force from the heatsink on the connectors are limited.

More information on the new implementation agreement can be found on the OIF's website.

For more information on optical transceivers and suppliers, visit the Lightwave Buyer's Guide.