The integrated electro-optic sensor is primarily a
polarization controller which exploits the linear electro-optic
effect (Pockels effect) of some crystals to measure the electric
field. In brief: application of an E-field to an electro-optic
medium changes the direction of light propagation. The
electrically-induced change in the birefringence is used to
produce a phase difference between the two orthogonal
eigenmodes propagating in the medium, and it leads to a
change in the polarization state of the output. Then an
analyzer converts the change in the polarization state to a
corresponding variation in the signal amplitude. The
amplitude-modulated light can be transmitted through the
optical fiber without losing its information content ,and finally
the information, namely the value of the applied E-field, can be
extracted by using an optoelectronic conversion unit.