Next generation ultra-broadband elastic optical networks maximize system-bandwidth utilization based on flexible diverse traffic demands accommodation. Research on novel network architectures and system components such as datarate variable transponders and hybrid amplification schemes are needed to allow geographical context adjustability as well as capacity system upgradeability from Gbps to Tbps. In this paper we report experimental validations on deployed Brazilian optical fiber of a data-rate variable transmitter feasible for both metro and long-haul applications. The developed transmission system exhibits spectral efficiencies of 4.58, 6.25 and 3.41 b/s/Hz for 1400, 700 and 4900 km of optical transmission respectively.