Asymmetric transmission device using Fe-doped KTa(x)Nb(1-x)O(3) crystal

A new type of asymmetric optical transmission device based on contradirectional two-wave mixing between an incident beam and its backward-scattering beams in Fe-doped KTa(x)Nb(1-x)O(3) crystal is demonstrated. The transmittance ratio of the beams propagating in opposite directions can be adjusted by a change in the angle between the incident beam and the c axis; the maximum ratio is nearly 50:1 at only one incident beam. Approximate solutions of two opposite transmittances are derived and discussed. It is possible to use this device as an optical isolator or an optical diode.