## 2 Results and Discussion
### Multi-Services Application over Polymer Fiber  
It has been clearly demonstrated that the PFGI-POF could be a challenging solution--not only for the high data rate baseband transmission (reasonably up to 10 Gbps) but also for the deployment of a RoF system--each of these subsystems being tested with fiber length from 50 m to 100 m. The high bandwidth capacities of the PFGI-POF both at 850 nm and 1,300 nm could be exploited to transmit simultaneously the two desired signals over the same fiber. The coarse wavelength division multiplexing (WDM) devices available in the glass fiber world are used to achieve dual transmission and to address the multi-services concept with PFGI-POF (Figure 1). According to the focused application dealing with the deployment of a home or office fiber network, the fiber length could be restricted to 100 m which would allow transmission simultaneously over a single PFGI-POF a 10 GbE signal at 850 nm and a radio signal at 1,300 nm, using the WDM devices. The evaluation of the penalties owing to the mismatching between the WDM devices and the PFGI-POF was proposed and realized by using the test setup depicted in Figure 20.  
Figure 19: _Cont._  
Figure 20: Overview of the test setup used to evaluate the performance of the multi-services concept on PFGI-POF. From the devices used, the lowest cost infrastructure currently achievable with components off the shelf is obtained. This photonic system appears to be a costless evolution from a typical 10 GbE network that offers the transmission of different services that potentially have overlapping spectra: only the low cost wavelength multiplexing devices are then needed to add a further service (radio signal) to a typical 10 GbE fiber network. The penalties and the performance of the developed system are then exhibited for the digital (850 nm path) and the radio over fiber (1,300 nm path) signals. The WDM devices used in these experiments have already been characterized and reported in [4]. The Bit Error Rate (BER) as a function of the received optical power is studied first (Figure 21). It is clear that the GigaPOF62-SR (length: 100 m) could minimize the BER in such a system compared to the Lucina-X PFGI-POF. A BER value close to \(10^{-11}\) is then achieved with the fiber produced by Chromis Fiberoptics. The best BER value obtained with the Lucina-X fiber (length: 100 m) is \(10^{-4}\). The core diameter and numerical aperture mismatching, between the Lucina-X plastics fiber (120 \(\upmu\)m) and the WDM devices based on 50 \(\upmu\)m core diameter glass multimode fiber, induce a mode filtering at the photoreceiver part resulting in additional penalties. A decrease of the fiber length close to 50 m obtains a \(5\,\times\,10^{-8}\) BER (Figure 21 left). Figure 21 (right) reports the BER evolution of the 10 GbE link based on the GigaPOF62-SR fiber with and without WDM devices. From the achieved BER values, it appears that the small core diameter mismatching between the fiber (62.5 \(\upmu\)m) under test and the WDM devices (50 \(\upmu\)m) induces fewer power penalties (less than 1 dB for a BER close to \(10^{-9}\)). An additional measurement is done with 50 \(\upmu\)m based patchcords to simulate the core diameter mismatching. Better results are obtained with such patchcords because the insertion losses of the WDM devices are not taken into account in such measurements. This last experiment demonstrates without any doubt that the penalties are due to the core diameter and numerical aperture mismatching between the WDM devices based on 50-\(\upmu\)m glass fiber and the PFGI-POF. These penalties have been evaluated respectively close to \(-9\) dB and \(-2.4\) dB for the Lucina-X and the GigaPOF62-SR.  
Figure 21: **(Left)** Evolution of the BER as a function of the received optical power for Lucina-X (50 m and 100 m), as compared to GigaPOF62-SR (100 m). The measurement is performed on the system including the WDM devices. **(Right)** Illustration of the penalties for the WDM devices used for the multi-services distribution.