Reflective semiconductor optical amplifiers (RSOAs) have recently received a lot of attention as cost-effective upstream optical transmitters for wavelength-division multiplexed passive optical networks. However, the modulation bandwidth of this semiconductor device is limited to ∼1.5 GHz and the device is largely used to accommodate <2.5-Gbps baseband signals. Recently we have proposed and demonstrated 10-Gbps operation of the RSOA using an optical delay interferometer (DI). The simple passive optical device acts as an optical equalizer as well as a vestigial side-band filter. In this paper, we present upstream transmission of 2-Gbps, 6-GHz radio signal using a directly modulated RSOA and a DI. Although the modulation bandwidth of our uncooled, transistor-outlook-can packaged device is only 1.2 GHz, not only does a 25-GHz DI equalize the limited bandwidth of the RSOA, but it also helps to generate a single sideband signal to make it resilient to the dispersion-induced RF fading.