The capacity growth driven by increasing traffic and the introduction of new devices and technologies has resulted in new functionalities in optical networks. The property of transparency enables compatibility between different system generations and the coexistence of multiple bit-rates without raising the global network cost. In a transparent network, the signals travel through many links and nodes without the need for opto-electronic regeneration, accumulating physical impairments. Therefore, standard point-to-point test-bed set-ups are no longer adequate to emulate signals propagating in transparent optical networks. New test-beds integrating the different heterogeneity cases due to the use of transparent cross-connects becomes necessary. In this paper, we present various test-bed realizations accounting for the following network heterogeneities: fiber link heterogeneity and neighbor changes while a signal propagates in the fiber. To be able to emulate such network heterogeneity, we present a double-loop set-up. Such a set-up is then used to assess the propagation results obtained by simulation and validate the quality of transmission (QoT) estimators.