Patent ID: 6747797
Filing Date: 2004-06-08
Classification: G02F

Abstract:
A four-port loop optical circulator comprising:a first, a second, a third and a fourth optical port for receiving an optical beam therein; a plurality of optical components for guiding a beam received from said first port to project from said second port, for guiding a beam received from said second port to project from said third port, for guiding a beam received from said third port to project from said fourth port, and for guiding a beam received from said fourth port to project from said first port; and wherein said plurality of optical components includes a walk-off crystal for generating a vertical optical path displacement for a vertical polarized optical beam and for passing a horizontally polarized optical beam therethrough maintaining a same optical path, a vertical displacement means for shifting an optical path along a vertical direction with a predefined vertical displacement for an optical beam transmitted with a particular polarization, and wherein said vertical displacement means is coupled to said walk-off crystal for guiding a beam received from said fourth port to project from said first port, and said plurality of optical components further includes a first birefringent crystal disposed on a left-hand side of said walk-off crystal for generating a first ordinary beam and a first extra-ordinary beam and a second birefringent crystal disposed on a right-hand side of said walk-off crystal for generating a second ordinary beam and a second extra-ordinary beam.