Demonstration of RSOA-based WDM PON Operating at Symmetric Rate of 1.25 Gb/s with High Reflection Tolerance

Design Issues in RSOA-based WDM PON

“…However, it requires the high injection power to the RSOA, and hence, it becomes less effective as the loss budget becomes high [5]. To solve this problem, we have proposed to use different modulation formats such as Manchester coding [5] and sub-carrier multiplexing (SCM) [12] instead of the conventional non-return-to-zero (NZR) format for the downstream signals. In this case, since the remodulation noise exists outside the upstream signal's bandwidth, the remodulation noise does not affect the BER performance of the upstream signal.…”

“…It has been demonstrated that the reflection-induced OBI noise was suppressed by broadening the optical spectrum of the signal (e.g., by applying the bias dithering [18] and by phase modulation [19]). Also, it has been reported that the reflection tolerance could be dramatically improved simply by using Manchester coding and SCM for the downstream signal [12], [20]. In these modulation formats, the signal bandwidth is much broader than the baseband signal of the downstream signal.…”

“…For example, Fig. 6 shows the experimental results on the effect of the reflections in the networks using NRZ and SCM for the downstream signal [12]. In this experiment, the bit rates of the upstream and downstream signals were 1.25 Gb/s.…”

Analog predistortion technique in remodulation based radio over high-speed access network for improving sensitivity

“…In contrast to previous works, sub-carrier multiplexing (SCM) based WDM-PONs in which down and upstream signals are transmitted over different frequency ranges have recently attracted much interest [8]- [10]. These networks do not need extra optical components for optical frequency/phase modulation and also do not suffer from a residual downstream signal, offering symmetric transmission rates for both up and downstream.…”

Deployment analysis of TDM/WDM Single Fiber PON with Colourless ONU Operating at 2.5 Gbps Subcarrier Multiplexed Downstream and 1.25 Gbps Upstream

“…However, these methods may not be low-cost, due to the components needed for modulation and detection of the up/downstream signals. A more cost-effective solution can be the use of a subcarrier multiplex (SCM) technique [3][4]. Using this technique upstream and downstream spectrums are not overlapped, and the system becomes more tolerant in front of Rayleigh backscattering.…”