## 3 Conclusions  
A microwave photonic filter architecture used to transmit digital signals coded in filtered microwave signals or band-pass windows located at 2.1 GHz and 4.2 GHz was presented. The choice of these band-pass windows was made due to the availability of electric devices as power dividers and mixers at our laboratory. However, other band-pass windows at 6.3 and 8.4 GHz can potentially be  
Figure 6: Eye diagram of the digital signal at (**a**) 50 MHz; (**b**) 100 MHz; and (**c**) 150 MHz. \begin{table}
\begin{tabular}{c c c c c c c} \hline \hline
**Frequency PPG (Pulse** & & & & **100** & & **150** \\
**Pattern Generator) (MHz)** & **50** & & & & **100** & & **150** \\ \hline Electrical Frequency (GHz) & 2.1 & 4.2 & 2.1 & 4.2 & 2.1 & 4.2 \\ Q-factor & 4.7 & 6.16 & 5.12 & 6.54 & 5.2 & 6.58 \\ Eye Height (mV) & 100.0 & 83.2 & 118.8 & 84.0 & 116.8 & 78.1 \\ Eye Width (ps) & 165.98 & 81.16 & 184.53 & 85.96 & 168.94 & 83.55 \\ Eye Jitter RMS (ps) & 10.51 & 5.41 & 9.37 & 5.23 & 10.20 & 4.90 \\ BER & \(1.35\times 10^{-6}\) & \(3.72\times 10^{-10}\) & \(1.58\times 10^{-7}\) & \(3.14\times 10^{-11}\) & \(1.03\times 10^{-7}\) & \(2.40\times 10^{-11}\) \\ \hline \hline \end{tabular}
\end{table} 
Table 3: Performance measurement of the digital signals transmission. used as electric carries. The significance of this approach is that the use of an MLD as an optical source allows for the generation of perfectly spaced band-pass windows in a \"natural\" way. The efficiency of the proposed scheme was evaluated with the transmission of digital signals at frequencies of 50 MHz, 100 MHz, and 150 MHz using the NRZ modulation format. These frequencies obeyed the PPG limitation, the maximum of which was 165 MHz. The NRZ modulation format allowed for the improvement of the dispersion tolerance due to its reduced spectrum width. Due to self-phase modulation (SPM), the effect strongly depends on the optical power of the source [15; 16]; we considered the results reported in [17] to determine the minimal optical power needed when the NRZ modulation format was used. The proposed system was free of FWM and XPM inter-channel effects given it was used a single channel transmission. According to the results displayed in Table 3, it is evident that the eye-opening was better for the 2.1 GHz case than for the 4.2 GHz case; however, the Q value was better for the latter case. The experimental results indicated that despite the considerable value of chromatic dispersion parameter exhibited by the optical fiber, acceptable values of the Q-factor, jitter, and bit-error-rate were obtained. On the other hand, note that the use of Equation (1) allowed for the reconfigurability of the filtered microwave band-pass windows in the function of the length of the optical link. For instance, considering \(D=15.81\) ps/nm\(\cdot\)km, \(\delta_{\lambda}=1.1\) nm, and \(L=12\) km, the use of Equation (1) gave \(f_{1}=4.7\) GHz, \(f_{2}=9.5\) GHz, \(f_{3}=14.3\) GHz, and \(f_{4}=19.13\) GHz. If \(L=50\) km, then \(f_{1}=1.1\) GHz, \(f_{2}=2.3\) GHz, \(f_{3}=3.4\) GHz, and \(f_{4}=4.6\) GHz. Therefore, a particular microwave band-pass window could be assigned to final users in the function of this distance. This reconfigurability is important because in a PON scheme, the optical link does not necessarily have to have the same length or distance. Finally, although that the data rates used in this experiment were modest, they were enough to deliver services like IP telephony, internet, streaming video, and high definition television (HDTV); therefore, the obtained results allow for the proposition of the use of this MPF architecture as a potential candidate for a PON scheme to distribute these services. In summary, our experiments demonstrated that the proposed system can be adapted to transmit analog or digital data. Conceptualization, methodology, preparation and writing the draft, A.G.C.-M., A.G.-J., and I.E.Z.-H.; resources, writing--review and editing, A.V.-M., and J.R.-A.