Ghetto WDM

As is fairly well known, optical receivers are rather wideband and can often receive signals anywhere between 1200 and 1600 nm. But what of the transmitters? Will their over and undertones spread out enough to fit into different WDM channels?

The idea behind this test was to run normal ER or ZR optics over a passive DWDM system (pretty much just a mux / demux). The transmitters with their over and undertones would spread out over several DWDM channels while the filter obviously would limit each signal to its given frequency range. Naturally, this would come with quite some attenuation and thus a hit to the range of this system and you wouldn't be able to use all DWDM channels but it could perhaps still be of some use as a quick hack.

Well, that's at least the theory that spawned this test.

After acquiring all the needed stuff, we

In retrospect, I actually have no idea why we did this with 10GE, we could probably have been as well off with GE, just to prove the point.

Eight ZR XENPAKs together with a pair of ER XENPAKs was borrowed from Tele2 and brought to our test facility where Bahnhof provided a Cisco 7609 with a RSP720-3CXL and two 6704 linecards to power the XENPAKs.

The spectrum analyzer used here