Due to the explosive traffic growth, future short-reach optical networks require high-capacity and low-cost optical transceivers with data rate beyond 100 Gbps. The Nyquist half cycle (NHC) single-sideband (SSB)-subcarrier modulation (SCM) achieves the most efficient bandwidth usage while ensuring zero intersymbol interference at the receiver. This work investigates the performance of short-reach link incorporating this modulation format and operating with direct-detection (DD) receiver and without optical amplification. Further, the work addresses the possibility of using multiplexing techniques to enhance the transmission capacity of the link. The receiver noise characteristics and bit error rate performance of 1550 nm optically carrier assisted-NHC SSB communication system is investigated analytically. The analysis takes into account various noise components in the DD receiver assuming no optical amplifiers are used in the link. The transmission performance of single-channel and WDM systems is simulated using Optisystem ver. 14.1 software. Results are presented for 16-QAM signaling with up to d 224 Gbps channel data rates.