Patent ID: 6636651
Filing Date: 2003-10-21
Classification: G02B,H04J

Abstract:
A four-port optical circulator, comprising:at least first, second, third and fourth optical input/output ports; first and second birefringent elements; a first polarization rotator optically coupled between the first and second birefringent elements, the first polarization rotator having one or more reciprocal polarization rotation sections and one or more optical path compensation sections; a non-reciprocal polarization rotator; a third birefringent element optically coupled to the non-reciprocal polarization rotator; a second polarization rotator optically coupled to the third birefringent element, the second polarization rotator having first and second half-wave plate sections and first and second optical path compensation sections; and a fourth birefringent element optically coupled to the second polarization rotator wherein the second birefringent element is disposed between the first polarization rotator and the non-reciprocal polarization rotator; wherein the circulator routes optical signals from the first port to the second port; wherein the circulator routes optical signals from the second port to the third port; wherein the circulator routes optical signals from the third port to the fourth port; wherein the circulator routes optical signals from the fourth port to the first port.