Matching filter (MF)-free digital filter multiplexed (DFM) single sideband (SSB) OFDM intensity modulation and direct detection (IMDD) dual-channel transmissions of 51.25Gbit/s over 25km SSMFs are experimentally demonstrated. It is shown that both transmission system impairments and digital filter characteristic variations can only lead to <1dB transmission performance degradations. Compared with the MF-free DFM-based double sideband (DSB) OFDM technique, the SSB technique has a similar receiver DSP complexity and provides almost twice the maximum signal transmission capacity. When compared with a conventional DFM technique incorporating a dedicated shaping and matching filter pair for each channel, the present SSB technique achieves a 10-fold reduction of receiver DSP complexity and 7.82Gbit/s of additional signal transmission throughput. We demonstrate these throughput and complexity advantages by modelling and measurement.