Not an expert in the field but it seems to me the key points are.

Generating any wavelength. (this article)

Accurately measuring wavelength. (otherwise there's no information benefit to arbitrary wavelength generation)

Wavelength insensitive holographic gates. (If they work on that frequency, and in a way that does not change the frequency) I don't know what properties such devices currently have

Assuming all of those, your ability to compute increases to your ability to distinguish wavelengths.

You could theoretically calculate much more in a way you could never detect, but then you get into some really interesting tree falling in a forest issues.