The optical switch, which is a key component of communication
networks, has been studied with various designs and
fabrication methods. Optical signal switching in a network
system is realized by optical switching devices which are
categorized into two types depending on whether they use optical
waveguides or free-space transmission. The free-space
transmission type optical switches are constructed with twoor
three-dimensional microelectromechanical system (MEMS)
mirrors. However, they have a disadvantage in terms of
the switching time because they are operated mechanically.
On the other hand, the waveguide type optical switches using
waveguides with the electro-optic (EO) effect are more promising
from a practical viewpoint because of their operational
Fig. 1 Classification and properties of Hologram optical swtich.
Fig. 2 Experiments to verify the principle of hologram optical switch.