Long-reach upstream >100-Gb/s by using directly modulated RSOAs for WDM PON

DUE TO the recent standardization activities of 100 Gigabit Ethernet (100 GbE), there have been growing interests in the 100-Gb/s passive optical network (PON). For example, it has been already demonstrated that 100-Gb/s PON can be realized by using the optical orthogonal- frequency- division- multiple access (OFDMA) technique . However, it should be noted that these 100-Gb/s OFDMA PONs are not intended to deliver 100-Gb/s service to each subscriber. In other words, the term “100- Gb/s” is nothing that it indicates the maximum per-wavelength transmission speed. Thus, if we assume that this network is consisted of 10 optical network units (ONUs), it can provide only 10-Gb/s service to each subscriber on average. This is very complicated to design this network and occupied the more space. To overcome this, we would be decided to provide capable of >100-Gb/s PON by using wavelength-division-multiplexing (WDM) technique. So in this paper we propose and demonstrate a long-reach wavelength - division- multiplexed (WDM) PON capable of providing >100-Gb/s service to each subscriber. For the cost-effectiveness (as well as the colorless operation of ONUs), we implement this network in loopback configuration by using directly modulated reflective semiconductor optical amplifiers (RSOAs) operating at >25-Gb/s(in this paper we use the RSOA operated at 25.78-Gb/s and also at 26-Gb/s) Thus, the >100-Gb/s upstream signal is obtained by combining the outputs of four RSOAs at each ONU using the coarse WDM (CWDM) technique, The long-reach operation over >100-km long single-mode fiber (SMF) link is accomplished by using Erbium-doped fiber amplifiers (EDFAs) at the remote node (RN). The results show that we can achieve the error-free transmission of the >100-Gb/s signals (obtained by combining four 25.78-Gb/s CWDM channels) with enough power margins.