
It appears that the ultimate limits regarding the operating frequency and other
characteristics of optical modulators, employing different mechanisms and materials,
are remote and to some extent unknown. These ultimate limits are dictated by the
pertinent fundamental issues, the remoteness from the limits mostly originating form
practical matters. Thus, the development of modulators of ever higher performance,
integration as well as capability for complex modulation formats, will certainly
remain a challenging research topic, especially experimentally, for a long time to
come. The application scope is ubiquitous in the quest for THz modulation rate ...