Optical Fiber Communications 4th Edition by Gerd Keiser

تمرين 7

Consider two plane waves X 1 and X 2 traveling in the same direction. If they have the same frequency but different amplitudes a i and phases i , then we can represent them by
X 1 = a 1 cos ( t - 1 )
X 1 = a 2 cos ( t - 2 )
According to the principle of superposition, the resultant wave X is simply the sum of X 1 and X 2. Show that X can be written in the form
X = A cos ( t - )
where
and