serializers from 25 to 5 Gbit/s. Since we can imagine that a parallel output of the queue can be used by the line card, we do not insert the serializer at the queue output, so that the overall electronic queue power consumption results to be on the order of 1.05 W. This is only an example, but it tells us that in the field of memories, it is not SO straight- forward to realize optical components that have lower power consumption with respect to electronics one even if the transmission line speed is as high as 100 Gbit/s. Another important point to verify is the switching speed, that is, the time the memory takes to pass from one state to the other. As a matter of fact, we have to take into account that a packet, one kbyte long, traveling at 100 Gbit/s, has a duration of 10ns Thus, the memory should commute in a time at least of the same order of magnitude of a packet duration. Optical switches based on MEMs have a switching time on the order of 1 ms; thus, they are quite far from this application. As far as SOAs are concerned, short amplifier can arrive at a commutation time of 1ns [52], SO they are completely suited for optical packet switching. Telecommunication Networks Last, but not least, it is important to evaluate the required delay line length. The packet has to be delayed minimum a packet length not to create interference on the delay line. If we use an optical fiber that has a refraction index of 1.5, the length required to delay a signal for 10ns is about m, that is, not a long fiber piece. If the delay line is realized by a waveguide in the InP chip where the SOAs are realized, it comes to be about 85 cm. Such a waveguide could be realized with the spiral design that is used for long waveguides in the SiO2 platform, but due to the small dimension of the InP wafers, this will probably not be economically convenient with respect to the integration with an external waveguide or with an external fiber. Up to now, we have discussed the possible architecture and performances of a simple optical queue. In re