## 6 Network Setup
### Principle of 3D-Ocdma-Pon  
To attempt to use the 3D-SWZCC code-based OCDMA system for a PON and tackle the aforementioned problems, this section offers a novel scheme for the WTS-OCDMA system by relocating the SCs in order to diminish the power decline and extent of the fibers among the transmitter (Te) and receiver (Re) nodes. The proposed architecture is able to significantly emulate the conventional scheme of a PON while keeping the great cardinality and capacity of a 3D-SWZCC-based OCDMA system. Although there are a lot of fibers used between OLT and ONUs, PON is employed to save the number of fibers, but this number is necessary to achieve spatial encoding as FBG and delay lines are needed to achieve the spectral and temporal encoding, respectively. There are advantages of the proposed OCDMA-PON compared to such state-of-the-art PON technologies. The optical CDMA technique is a point-to-multipoint technology where each end-user picks up its own message from the broadcast signal. Similarly, PON architecture is also point-to-multipoint access technology with passive components, such as splitters, couplers, fiber-optics, etc., where potentially the cost is reduced. \begin{table}
\begin{tabular}{c c} \hline \hline
**Parameter** & **Value** \\ \hline PD responsivity & 1 A/w \\ \hline FBG bandwidth & 0.8 nm \\ \hline WLS spectrum bandwidth & 5 nm \\ \hline Data rate & 0.622, 1, 1.5 and 2 Gbps \\ \hline MZM extinction ratio & 30 dB \\ \hline Thermal noise coefficient & 1.8\(\times 10^{-23}\) W/Hz \\ \hline Coupling coefficient & 0.5 \\ \hline Cut-off frequency & 0.4665, 0.75, 1.125 and 1.5 GHz \\ \hline Number of active users & 8 \\ \hline Shot noise distribution & Gaussian \\ \hline Dark current & 5 Na \\ \hline Modulation format & NRZ \\ \hline SMF length & 30 km \\ \hline Coupling coefficient & 0.5 \\ \hline Insertion loss & 0 dB \\ \hline Transmitted power & \(-100\) dBm \\ \hline MZM extinction ratio & 30 dB \\ \hline \hline \end{tabular}
\end{table} 
Table 4: System parameters used for network simulation. As the amount of energy that can be consumed by an AON is more than that consumed by a PON, a PON is therefore considered overall to be an energy saver. This contributes to saving the power consumed by the OCDMA system if the OCDMA and PON have emerged in the same network. In order to obtain results that can be described as near the practical performance of such a system, some factors should be taken into consideration, such as the non-linearity characteristics of a single-mode fiber (SMF) and noise sources, represented by the thermal noise coefficient. In accordance with the 3D-SWZCC-OCDMA system model which we propose to implement for a PON, we include six users: two users appropriated for spectral encrypting, two users appropriated for temporal encrypting, and two users appropriated for spatial encrypting, as shown in Figure 13. Thus, the total code length is equal to eight (\(L=2\times 2\times 2=8\)). As shown in Figure 14, as in other PON systems, the proposed network can be partitioned into the following two sections: an optical line terminal module (OLT) at the central office and optical network units (ONUs) at the subscriber's premises to replicate a basic PON. In addition, Optical Distributed Network (ODN) contains a long-span light-wave path named feeder fiber that carries the three-dimensional encoded spectrum from the central office to the remote node that houses a coupler module to splits the network into a point-to-multipoint domain. The OLT of our proposed system contains \(K_{1}\times K_{2}\times K_{3}\) transmitter units; in our case, there are eight units, and each one of them contains a pseudorandom bit sequence (PRBS) generator, non-return to zero (NRZ), and a white light source (WLS) that is responsible for the generation of optical bandwidth. It is bonded with a Mach-Zehnder Modulator (MZM), which functions as a signal transformer that transforms electrical signals into optical signals.