Recently, the most efficient technologies to provide high-quality service and support the ever-growing data traffic in worldwide Passive Optical Networks (PONs) are Radio over Fiber (ROF) and Wavelength Division Multiplexing (WDM). Sub-Carrier Multiplexing (SCM) provides high capacity transmissions at lower costs and enables fiber based wireless access. It uses optical components for high performance but limitations of electronic components cause electronic bottleneck, which leads to limit the bit rate, number of users and the overall system performance. In this paper, An attempt has been made to extend the number of users up to 20 users with a bit rate of 10 Gbps , a transmission distance of up to 100 Km with various fiber cables and reduce the number of electronic components for the detection of baseband signals . Here the blend of WDM and Sub-Carrier Multiplexing (SCM) with modified differential phase shift keying (DPSK) modulation provides a more flexible platform and high dispersion tolerance for high-speed optical transport networks with high efficiency of optical bandwidth.