Experimental setup. There are two parts of the setup, (a) state preparation and indicator state encoding module (with a 3D view, a side view, and a top view) and (b) measurement module with its four statuses in top view. (c) Light beam array, the view comes from a person who faces the light source at the end of (a). The nine paths will then enter the measurement module. The paths have two coordinates, the horizontal one tells which interferometer arm a path belongs to, and the vertical one tells the layer information of a path. Each indicator state is labeled with a pink rectangle box in (a) and with a blue rectangle box in (c). Measurement bases labeled in (b) are used to perform tomography of each layer of the light beam array in (c). BD1 and BD2 are the correspondence of the first BS in Fig. 2, and BD5 and BD6 in measurement module can be seen as the correspondence of the second BS, which has nine light paths.