Patent ID: 7412132

Claim:
A fiber optic isolator comprising: an input collimator positioned along an optical axis and configured to receive a beam of light through an optical fiber along the optical axis and to emit the beam of light at an angle with respect to the optical axis; a first birefringence crystal having an input face and an output face, wherein the first birefringence crystal is positioned along the optical axis and configured to receive the beam of light from the input collimator, wherein the input face is positioned at an angle with respect to the optical axis, and wherein the first birefringence crystal separates the beam of light into an e-beam and an o-beam; a waveplate positioned along the optical axis and configured to receive the e-beam and the o-beam from the first birefringence crystal, wherein the e-beam and the o-beam have a polarization and wherein the waveplate is configured to rotate the polarization by 45 degrees in a first direction; a Faraday rotator perpendicularly positioned along the optical axis and configured to receive the e-beam and the o-beam from the waveplate and to rotate the polarization by a further 45 degrees in the first direction; a second birefringence crystal having an input face and an output face, wherein the second birefringence crystal is positioned along the optical axis and configured to receive the e-beam and the o-beam from the Faraday rotator, wherein the output face of the second birefringence crystal is positioned at an angle with respect to the optical axis and wherein the faces of said first and second birefringence crystals are selectively positioned in parallel so that the angle of the output face of the second birefringence crystal matches the angle of the input face of the first birefringence crystal and wherein the second birefringence crystal combines the e-beam and the o-beam and emits the combined beam at an angle off of the optical axis; and an output collimator positioned along the optical axis and configured to receive the combined beam from the second birefringence crystal and to reorient the combined beam along the optical axis and at an angle with respect to the optical axis.