chapter  10
24 Pages

Silicon High-Speed Modulators

ByAnsheng Liu, Frederic Y. Gardes, Ling Liao, Rebecca Schaevitz, Graham Reed, and Mario Paniccia

Fiber optics is well established today due to the large capacity and reliability it provides, but it has a clear disadvantage in cost. Furthermore, components are typically large and expensive due to bulky ˜ber elements. ™is, linked to the time consuming assembly and packaging required for precision alignment of micro-optics with dimensions of the order of micron, has led to increasing interest in the possibility of building devices integrated on a single chip of transparent material and, consequently, bene˜tting from the much smaller footprint in integrated photonics. Ever since the earliest research on optical circuits, dating back to the 1970s, there have been visions of an optical superchip [1,2], containing a variety of integrated optical components to carry out light manipulation (generation, modulation, detection, switching, ˜ltering, and ampli˜cation). In the early days of integrated photonics the work was associated with ferroelectric materials such as lithium niobate, and III-V semiconductors such as the gallium arsenide and indium phosphide based systems. ™is was mainly due to a large electro-optic eŸect enabling high modulation speed in the case of lithium niobate, and the possibility to integrate a source and other critical components in the case of III-V semiconductors.