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US 6,212,008 B1Granted
Compact polarization insensitive circulators with simplified structure and low polarization mode dispersion
AssigneeNew Focus, Inc.
InventorsPing Xie, Yonglin Huang
Life of this patent
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Abstract
Disclosed are optical circulators possessing a longitudinal axis, the optical circulator including a first and second walk-off crystals optically coupled in a substantially equivalent optical distance, cascaded walk-off configuration, together with systems including such circulators, and methods of circulating optical signals.
Claims29
An optical circulator possessing a longitudinal axis, the optical circulator comprising:
- first and second walk-off crystals optically coupled in a equivalent optical distance, cascaded walk-off configuration, and wherein the optical circulator further comprises a low order half wave plate, and the low order half wave plate being located between and adjacent to each of the first and second walk-off crystals along the longitudinal axis.
An optical circulator having a longitudinal axis comprising:
- a first beam displacer/combiner that displaces at least one optical beam into two polarized component beams and combines at least two polarized component beams to form an optical beam;
- a first nonreciprocal rotator, optically coupled to the first beam displacer/combiner distally along the longitudinal axis, for rotating a polarization orientation of the polarized component beams;
- a first walk-off crystal, optically coupled to the first nonreciprocal rotator distally along the longitudinal axis, for walking-off only one of the polarized component beams;
- a second walk-off crystal, optically coupled to the first walk-off crystal distally along the longitudinal axis, for walking-off the other polarized component beams;
- a reciprocal rotator, optically coupled distally from and adjacent to the first walk-off crystal and proximally from and adjacent to the second walk-off crystal;
- a second nonreciprocal rotator, optically coupled to the second walk-off crystal distally along the longitudinal axis, for rotating the polarization orientation of the polarized component beams;
- and
- a second beam displacer/combiner, optically coupled to the second nonreciprocal rotator distally along the longitudinal axis, that displaces at least one optical beam into two polarized component beams and combines at least two polarized component beams to form an optical beam.
5 more elements
A method of circulating optical signals comprising:
- optically coupling a first and second walk-off crystal in an equivalent optical distance, cascaded walk-off, configuration, and
- optically coupling a low order half wave plate between and adjacent to each of the first and second walk-off crystals.
Dependencies are inferred from the claim text.