Just like say swapping a green for a red LED, the wavelength emitted is a function of the IR LED & has nothing to do with the energising circuit! Most IR data senders & the traditional 3 legged receivers are pretty broad responding anyway. Hence I doubt it'd make a difference which wavelength was used.
Thought: I assume you ARE aware that the Picaxe-08M has enhanced Sony style 38kHz IR sending & receiving already inbuilt? IR data comms has been pretty much revolutionised by this-it's almost too easy!
