In an optical communications system, the thermal pathway for dissipating heat generated by clock and data recovery (CDR) circuitry of an optical communications module is a separate from the thermal pathway that is used to dissipate heat generated by other components of the module. The CDR circuitry is external to the module and is provided with its own heat dissipation device. Keeping the CDR circuitry external to the module and providing it with its own heat dissipation device decouples the thermal pathway for dissipating heat generated by the CDR circuitry from the thermal pathways used for dissipating heat generated by other components of the module. This results in more effective heat dissipation and better component performance.