I have a 40GBASE-SR4 QSFP transceiver which can be used for 4x10G SFP+ communications using a 40G QSFP+ to 4x10G SFP+ multi-mode optical spliter. I am looking for an LR (single-mode) equivalent of this SR transceiver, but can't find any.
I fear that fundamentally 40GBASE-LR4 cannot be used for 4x10G because the data is delivered as four wavelengths over the same fiber, whereas 40GBASE-SR4 can be used for 4x10G because the data is delivered over four parallel fiber lanes.
Can 40GBASE-LR4 be used for 4x10G?
Best Answer
You are correct. SR4 works because it's four fibres. LR4 doesn't because it's four lambdas. Even if you break out each one -- good luck finding 10G-LR optics at the exact wavelengths LR4 requires, the module itself doesn't support operating at 4x10G -- the data rate on most is 40G only.