array waveguide grating

currently i am doing research in awg(array waveguide grating) and i am facing a problem on the transfer function of the awg as i got a pulse shape act like a multiple filter, and i dont know whether is it correct or not.

secondly is i am facing problem on the frequency spectrum of my input signal as i cant generate it properly in frequency spectrum, firstly i generate 100 of random bits then each '1' bit i represent with a gaussian pulse shape, for '0' bit it is zero, then i multiply it with exp(jwt) with different frequency as i got 8 input signals which means that is 8 x 8 awg, after i done this all i cant manage to plot out the frequency spectrum.

thirdly, how to multiplex the 8 signals.

p/s: i am writing the simulation code in MATLAB

thanks for your all help, very appreciate it if anyone can solve my probs.