Lett., 11(2), 191, 1999.) EA modulators suitable for modulation up to 40 Gbit/s have been introduced on the mar- ket and a summary of the characteristics of practical modulators is reported in Table 5.7. 5.5.3 Integrated Optical Components It is quite spontaneous to think that, since several optical devices can be fabricated with planar technologies, the evolution of optical devices should somehow repeat the evolution of electronics through multiple function integration and large-scale integration circuits. In the optical field there are even two possible integration platforms: silicon and III-V alloys, both compatible at first glance with integration of optical devices with electronics. In practice, there have been several attempts to develop a technology platform for inte- grated optics and the results of these attempts always have been inferior to expectations. TABLE 5.7 Characteristics of Practical Lumped and Traveling-Wave EA Modulators Architecture Lumped Traveling Wave Small signal modulation bandwidth 45 GHz 60 GHz Operating bit rate 10-40 Gbit/s 10-40 Gbit/s Operating wavelength 1550 nm 1550 nm Optical insertion loss (connectorized) 6.0 dB Polarization-dependent loss -0.5 dB -0.7 dB Maximum input optical power 10 dBm 8 dBm OPTICAL RETURN LOSS 25 dB 35 dB Optical on/off extinction ratio (at DC) 12 dB 15 dB DC reverse bias voltage Footprint (w/electrical connections, 30 X 32 mm 40 X 25 mm w/o pigtail) Telecommunication Networks As we will see in Chapter 10 a similar attempt leveraging the III-V platform is ongoing and it is possible that it will have success. But also in this case, the foundation of this pos- sible success will be different from the causes of the success of microelectronics, since it is founded more on the performances allowed by optical integration than on the diffusion of a pervasive generation of low-cost new optical devices. There are essentially two causes of this evolution: one more fundamental and the other related to the use of optical components. 5.5.3.1 Electrons and Photons in P