Single fiber **and** single wavelength are **fundamentally incompatible.** You either need two fibers (send at each end connected to receive at the other end) and one wavelength is fine, or you need two different wavelengths so that data can travel both ways over the same fiber without conflict. 

10Gb does not include a half-duplex option, which would be the only other way to get one fiber and one wavelength (and half the speed, or less than half the speed.)

"CWDM" means **C**oarse **W**avelength **D**ivision **M**ultiplexing" and is another way of saying "not one wavelength" and the "coarse" part also says "wavelengths that are not terribly close to each other" such as 1490/1510, 1310/1490, etc...

Dense WDM (DWDM) implies wavelengths that are much closer to each other.