They differ in the type of laser and other components performing various functions inside the transceiver. For example, dual rate transceivers deal with two transmission speeds meaning signal operations more demanding and challenge manufacturers to ensure good signal integrity.
Moreover, in the case of OTN and Ethernet standards, we face other levels of tolerance for signal parameter deviations. For example a bit-rate tolerance parameter for OTN equals +/- 20 ppm, and for Ethernet, +/- 100 ppm. For these reasons dual rate transceivers are more expensive than single rate transceivers of a similar type.
From the user’s point of view, the purchase of dual rate transceivers is justified in cases where transceivers are designed to work in OTN transmission systems or when current infrastructure based on Ethernet standards is being switched to using OTN transmission technology.
In the case when switches and routers work only in the Ethernet network environment it is better to use less expensive single rate transceivers.
The key features of dual rate and single rate optical transceivers are:
