We introduce a particular photonic device (a Silicon Photonics Add-Drop Multiplexer), which is exploited to develop the testing solutions. First we focus on its own peculiarities (among the others, continuous tuneability along the C+L band, absence of any spectral repetition and polarization independence). Then, the internal design and the choice of its bui lding blocks are addressed. In particular, the latter is supported by suitable numerical simulations. Finally, a preliminary characterization is performed and performance of the device is assessed (in terms of spectral response and transmission quality).