Optical circulator
AssigneeU.S.A Kaifa Technology, Inc.
InventorsVINCENT AU-YEUNG, QING-DONG GUO, XING LONG WANG
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Abstract
An improved optical circulator transfers light from a first optical port to a second optical port, and from the second port to a third port. The circulator has non-reciprocal polarization rotators, birefringent beam splitters and combiners, and a polarization-dependent light bending device comprising two tapered birefringent plates. The light bending device compensates for an angle between a first light beam emanating from the first port and a second light beam propagating to the third port. The existence of this angle allows the first and third fibers to be coupled to the light beams using a single lens.
Claims20
An optical circulator for coupling light from a first fiber to a second fiber and from said second fiber to a third fiber, said first fiber and said third fiber being located adjacent to each other along a longitudinal axis, and said second fiber being located opposite said first and third fibers along said longitudinal axis, said optical circulator comprising along said longitudinal axis in sequence from said first fiber to said second fiber:
- a) a first lens for guiding light from said first fiber and to said third fiber;
- b) a first block of birefringent material for separating and combining mutually orthogonal polarizations;
- c) a first compound polarization rotator for rendering mutually parallel polarizations orthogonal and mutually orthogonal polarizations parallel, said first compound polarization rotator comprising first and second non-reciprocal polarization rotators;
- d) a polarization-dependent light guiding device, comprising a first and a second tapered plates of birefringent material, said first plate having a first optic axis, said second plate having a second optic axis, said first optic axis and said second optic axis being mutually perpendicular;
- e) a polarization-dependent beam deflector comprising a second block of birefringent material,
- f) a second compound polarization rotator for rendering mutually parallel polarizations orthogonal and mutually orthogonal polarizations parallel, said second compound polarization rotator comprising third and fourth non-reciprocal polarization rotators;
- g) a third block of birefringent material for separating and combining mutually orthogonal polarizations;
- and
- h) a second lens for guiding light to said second fiber and from said second fiber,
- wherein light passing from said first fiber exits said first lens at an angle θ with respect to said longitudinal axis, and said light passing from said second fiber exits said light guiding device at an angle φ with respect to said longitudinal axis.
An optical circulator for coupling light from a first fiber to a second fiber and from said second fiber to a third fiber, said first fiber and said third fiber being located adjacent to each other along a longitudinal axis, and said second fiber being located opposite said first and third fibers along said longitudinal axis, said optical circulator comprising along said longitudinal axis in sequence from said first fiber to said second fiber:
- a) a first lens for guiding light from said first fiber and to said third fiber;
- b) a first block of birefringent material for separating and combining mutually orthogonal polarizations;
- c) a first compound polarization rotator for rendering mutually parallel polarizations orthogonal and mutually orthogonal polarizations parallel;
- d) a polarization-dependent light guiding device, comprising a first and a second tapered plates of birefringent material, said first plate having a first optic axis, said second plate having a second optic axis, said first optic axis and said second optic axis being mutually perpendicular, and said second optic axis being skewed with respect to said longitudinal axis;
- e) a second compound polarization rotator for rendering mutually parallel polarizations orthogonal and mutually orthogonal polarizations parallel;
- f) a second block of birefringent material for separating and combining mutually orthogonal polarizations;
- and
- g) a second lens for guiding light to said second fiber and from said second fiber,
- wherein light passing from said first fiber exits said first lens at an angle θ with respect to said longitudinal axis, and said light passing from said second fiber exits said light guiding device at an angle φ with respect to said longitudinal axis.
Dependencies are inferred from the claim text.