Patent ID: 6404536
Filing Date: 2002-06-11
Classification: G02B,G02F

Abstract:
A polarization independent tunable acousto-optical (AO) filter to transmit an input light beam into a first output light beam unaffected by acoustic waves and a second output light beam diffracted by acoustic waves, which filter comprises:a first polarization beam displacer/combiner to separate the input light beam into a first polarized light beam and a second polarized light beam orthogonal to each other; a first polarization rotator to rotate the polarization of the first polarized light beam output from the first polarization beam displacer/combiner by 90 degrees; an AO device to receive the first polarized light beam and the second polarized light beam output from the first polarization rotator and to generate an AO effect that rotates light of a specific wavelength by 90 degrees; a second polarization beam displacer/combiner to receive the first polarized light beam and the second polarized light beam output from the AO device and separate a third polarized light beam from the first polarized light beam and a fourth polarized light beam from the second polarized light beam; a second polarization rotator to rotate the polarization of the second polarized light beam and the fourth polarized light beam output from the second polarization beam displacer/combiner by 90 degrees; a third polarization rotator to rotate the polarization of the third polarized light beam and the fourth polarized light beam output from the second polarization rotator by 90 degrees; and a third polarization beam displacer/combiner to combine the first polarized light beam and the second polarized light beam into the first output light beam and the third polarized light beam and the fourth polarized light beam into the second output light beam.