se of a WC based on the amplifier with the parameters in Table 10.1 is reported in Figure 10.13. The input signal, at the wavelength of 1550 nm, is shown in Figure 10.13a. The incoming signal is affected by a strong additive noise (the optical SN is about 10 dB), and if detected, would cause an important ISI effect. As a matter of fact, the dynamic range is as low as 8.8 dB and the ISI index accumulated during propaga- tion is 18%. The incoming signal is amplified by a first SOA with a linear gain of 10 dB, and then it is inserted into the nonlinear SOA with a peak power of 14 dBm. The probe, 100 GHz apart, is produced by the integrated DBR and injected into the SOA at a power of -5 dBm. The behavior of the amplifier gain is shown in Figure 10.13b, where gain saturation in consequence of the high modulated signal is clearly shown. The output signal at the probe wavelength is reported after the filtering with a resonant filter in Figure 10.13c. It inverted with respect to the original signal, and besides wavelength conversion, its trans- mission quality is quite improved. The optical SN is about 17.5 dB, with a gain of 7.5 dB with respect to the input signal, the dynamic range is about 14.8 dB, with a gain of 6 dB with respect to the input signal, and the ISI index is reduced to 5%. TABLE 10.1 A Few Important Parameters of a Very Long, Highly Nonlinear SOA SOA length Carriers lifetime Superposition integral Bulk diffraction index Linewidth enhancement factor Local unsaturated gain (enclosing losses) 6 X 104 m-Superscript(1) Local saturation power Next Generation Networking: Enabling Technologies, Architectures, and Performances Time (ps X 10) Time (ps X 10) Time (ps X 10) FIGURE 10.13 Time domain response of a WC based on an SOA amplifier with the parameters in Table 10.1. The input signal is plotted in (a), the gain behavior during signal amplification is reported in (b), while the output signal, inverted and regenerated, is shown in (c). The potential of this device is interesting, but it also has a certain numb