The Cisco ones from FS.com are great, I haven't had to do DWDM but everything I have had from FS.com has been 100% fine. If you know the brand of switch it will go in, they can match to that for you.

XFP – the first of the small form factor 10GbE optics.Presents LC connectors. SFP+ – a 10GbE optics using the same physical form factor as a gigabit SFP. Because of this, many of the small ...

Cisco’s Catalyst C1300-8MGP-2X enterprise-class Ethernet switch manages small and medium-sized networks at speeds up to 10Gb. It has eight wired interfaces, a 120W PoE, and two 10G SFP sockets ...

SFP-DD Multi-Source Agreement Group has updated its 5.0 hardware specifications and drawings for the SFP-DD, SFP-DD112, and SFP112 pluggable modules.