Answer:
The answer is Coarse wavelength division multiplexing (CWDM)
Explanation:
CWDM is the wavelength designed for short- distance connections and has only a few lambdas. It is mostly used nowadays as a type of wavelength technologies deployed in cities and inner access ways. It is inexpensive and thus a cost effective wavelength division multiplexing. Cost effective lasers can be used in CWDM due to the spacing of about 20nm between its wavelengths.
I've added my own code in a picture below. I didnt really notice any error, which would cause problems in your code. The main issues I had with your code is purely readability. You should start using the format function along with the curly brackets to concatenate variables into strings. You should also start doing even += 1 instead of even = even + 1. I also tweaked your range function. Simply putting n makes it much easier to read and understand.