 magnitude as the budgets evaluated in the case of the WDM-PON. There is no relevant difference from this point of view, as it was intuitive from the fact that fiber propagation and splitting losses are not strongly dependent on the signal wavelength in the band relevant for fiber access. Optical link budget: XWDM-PON versus XG-PON1 Standardization prescribes for the XG-PON1, a link budget sufficient to have a reach compatible with GPON B+ and GPON C. Taking into account the slightly higher losses experimented by XG-PON1 wavelengths with respect to the GPON wavelength and a set of other differences in the transmission line between GPON and XG-PON1, a budget of 29 and 31 dB, depending on the comparison with GPON B+ or GPON C, results. A similar prescription does not exist for XWDM-PON, and a real power budget will be available only after that the first industrial product is produced in volumes. Presently, Ethernet components and equipment implementing 10GbE are designed for top class Ethernet applications, if not for the carrier core network as backhauling of the core machines. Thus, these systems can provide good trans- mission performances. For example, a 10GbE XFP designed for the switches placed at the core of the private network of a large corporate or for the public Ethernet switches of the core metro network are equipped with APD photodiodes and nar- row line width DFB lasers, and generally assures a power budget in between -30 and -34 dBm. It is to be noted that an XWDM-PON equipped with interfaces that guarantees a power budget of -32 dBm can cover a reach of about 25km. This is not for free naturally, since we have to remember that different from the XG-PON that has a single transmitter into the OLT, an XWDM-PON has a maximum of 16 transmit- ters of different colors. 11.5 Enabling Technologies for Gbit/s Capacity Access The problem that optical and electronics technology has to solve in the case of next gen- eration access is to allow gigabit class equipment to be realized and deployed in huge volumes at