In this paper, we introduce a recent development of EO polymers, which are expected to achieve ultra-fast optical modulator and optical switching devices. EO polymers shown in this study are traditional host-guest PMMA, side-chain polymers, and hyper-branched polymers. Especially, hyper-branched polymers resulted in larger electro- optical activity due to the high density of their nonlinear optical chromophore and high order of electro poling efficiency. EO polymers are explored for the use as polymer optical modulators that demonstrated fast data transfer up to 100 Gbs, which is much higher than previous inorganic devices. Furthermore, polymer devices work with very low electric power, promising wide applications in future optical telecommunications technology.