We suggest using the experimental setup given in [15] by carrying out the following change: We will increase the distance, equally and sufficiently, between the mirror and polarized beam splitter present on one side and between the other mirror and beam combiner present on other side in the experimental apparatus shown in FIG 1 below which is actually Figure 5 in [15] taken with thanks. We then suggest to carry out imaging after suitably predefined regular time intervals and compare these images of transverse amplitude, phase, (and intensity) of coherent electromagnetic field. It is our guess that the images will be identical as long as no gravitational waves pass through the apparatus and cause changes in the distance between the mirror and polarized beam splitter present on one side as well as in the distance between the other mirror and beam combiner present on other side in the experimental apparatus shown in Figure 5 in [15] due to squeezing and stretching of space-time fabric. So, the changes that will be observed will occur in the images only due to the passing of gravitational waves through the apparatus. Due to passing of the gravitational waves through the apparatus the squeezing and stretching of the paths for rays will cause the change in the images of transverse amplitude, phase, (and intensity) to be taken at regular intervals. The observed changes in the images will offer a conclusive proof for the existence of gravitational waves!