## 3 Experiment and Results  
We have experimentally validated the proposed scheme, achieving complete reception of a broadband signal within the 2-18 GHz range using 16 sub-channels, each with a 1 GHz bandwidth. A continuous optical carrier at a wavelength of 1552 nm, generated by a laser (Emcore 1782), has an output power of 17 dBm. This optical carrier is evenly split into upper and lower paths by a 50:50 optical coupler. The upper path's optical carrier enters POLM\({}_{1}\) (Versawave, PM43 AAP) and is modulated by a single-tone signal RF\({}_{1}\), producing a polarization-multiplexed three-line optical frequency comb. A broadband signal RF\({}_{2}\) with a bandwidth of 40 MHz, generated by an arbitrary waveform generator (Agilent, 8256D), is injected into POLM\({}_{2}\) as the signal to be received. The use of a 40 MHz broadband signal for testing is due to experimental constraints that prevent the direct generation of the required broadband RF signal; instead, a series of broadband signals within the 2-18 GHz frequency range with a 40 MHz bandwidth are used to verify the channelization reception function for this frequency segment. The signal output from POLM\({}_{2}\) (Versawave, PM43 AAP) is amplified to 18 dBm by an EDFA\({}_{1}\) (Keopsys), adjusted in polarization direction by PC\({}_{1}\) to an angle of 45\({}^{\circ}\) with the PBS\({}_{1}\) principal axis, and then channel separation is performed using an OBPF (Yenista XTM-50), followed by connection to the RF input of a DP-IRR. The lower path's optical carrier is first directed into an AOM (IPF-1000-3 FP) to achieve a frequency downshift of 500 MHz. The advantage of using AOM for frequency shifting is that it does not produce spurious harmonics. The frequency-shifted optical carrier then enters the DPMZM (FUJITSU FTM7962 EP) on its upper and lower arms, where it is modulated by local oscillator signals LO\({}_{1}\) and LO\({}_{2}\) with frequencies of 4 GHz and 8 GHz, respectively, for carrier-suppressed double-sideband modulation. The spectrum output from the DPMZM is shown in Figure 3.  
The signal output from the DPMZM is amplified to 20 dBm by an EDFA\({}_{2}\) (Keopsys CEFA-C-HG-PM). After amplification, the signal is adjusted by PC\({}_{2}\) to set the angle such that the signal from the DPMZM makes a 45\({}^{\circ}\) angle with the principal axis of PBS\({}_{2}\). An OBPF (EXFO XTM-50) is then used to direct the optical local oscillator signal with a frequency of \(\omega_{c}-\omega_{fs}-\omega_{LO2}\) into the local oscillator input of the DP-IRR. Figure 4a presents the test results for the spurious-free dynamic range (SFDR) of channel 1. The SFDR was measured using a dual-tone signal with central frequencies of 2.8 GHz and 2.81 GHz, down-converted by an LO signal with a central frequency of 3.5 GHz. Table 1 displays the SFDR values for the remaining sub-channels, which are all within the range of 94 dB-Hz\({}^{2/3}\) to 96 dB-Hz\({}^{2/3}\). Figure 4b shows the channel response test results for channel 1. The RF signal was tested for the reception power of all signals within the channel with a starting frequency of 2 GHz, an end frequency of 3 GHz, and a step interval of 50 MHz. The power fluctuation was observed to be within 1.5 dB, indicating that the channel has a good amplitude response. The power fluctuations for the other channels were all found to be less than 2 dB. To evaluate the channelization reception and image rejection capabilities within the 2-18 GHz range, we utilized broadband RF signals with a bandwidth of 40 MHz and center frequencies of 7.9 GHz and 9.1 GHz, down-converted with an LO signal at a center \begin{table}
\begin{tabular}{c c c c c c c c} \hline \hline
**Sub-Channel** & **1** & **2** & **3** & **4** & **5** & **6** & **7** & **8** \\ \hline SFDR (dB-Hz\({}^{2/3}\)) & 96.8 & 94.7 & 95.5 & 94.4 & 94.8 & 96.6 & 94.1 & 95.3 \\ sub-channel & 9 & 10 & 11 & 12 & 13 & 14 & 15 & 16 \\ SFDR (dB-Hz\({}^{2/3}\)) & 94.5 & 93.8 & 94.2 & 93.7 & 96.7 & 95.3 & 94.3 & 95.8 \\ \hline \hline \end{tabular}
\end{table}