We propose a simple two-channel mode-group-divisionmultiplexing (MGDM) system operating in the 0.8 mu m region over the standard single-mode fiber (SSMF). For the cost-effectiveness, we implement its receiver by using only two photodetectors (PDs) [instead of three PDs required for the detection of the LP01, LP11a, and LP11b modes]. We then detect the signal carried by the LP01 mode by using a PD and a mode filter. On the other hand, the other signal carried by the LP11 mode group is detected by using another PD and a multiple-input single-output equalizer (i.e., by subtracting the signal carried by the LP01 mode from the multiplexed signal). For a demonstration, we transmit 2 x 28 Gb/s MGDM on-off keying signal operating at 852.6 nm over 2.2 km of the SSMF by using the proposed technique. The results show that we can achieve the bit-error rate of <3.8 x 10(-3) for both the LP01 and LP11 modes. (C) 2021 Optical Society of America under the terms of the OSA Open Access Publishing Agreement