> So "These wavelengths are generated from an array of lasers, forming a frequency comb" is using "frequency comb" to mean something else in that sentence. Yes

> So "These wavelengths are generated from an array of lasers, forming a frequency comb" is using "frequency comb" to mean something else in that sentence. Yes, "frequency grid" would have been better terminology. Common spacing for WDM is 50 GHz between adjacent frequencies (it's ITU spec'd iirc), and those rely on feedback system to maintain the spacing precision.