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US 6,154,581 AGranted
Multiple port, fiber optic circulator
AssigneeADC Telecommunications, Inc.
InventorsLiang-Ju Lu, B. Barry Zhang
Life of this patent
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Abstract
A reflective circulator includes a birefringent splitting and combining element, a non-reciprocal polarization rotator, and birefringent translating element. Some embodiments of the circulator include an inverting reflector. The circulator can be scaled to have a large number of ports arranged in a one dimensional array or in a two dimensional pattern, such as an array.
Claims47
An optical circulator, comprising:
- a birefringent splitting and combining element configured to split a beam of light propagating in a forward direction into first and second light paths having mutually orthogonal polarizations;
- an inverting reflector configured to reflect light travelling forward along the first light path to travel in a reverse direction along a third light path parallel to the first light path, and to reflect light travelling forward along the second light path into a reverse direction along a fourth light path parallel to the second light path,
- a first non-reciprocal polarization rotator configured to rotate polarization directions of light propagating along the first, second, third and fourth light paths from the first splitting and combining element by approximately 45.degree.;
- and
- a birefringent translating unit configured to laterally displace a light beam propagating therethrough with a first polarization direction and to transmit without lateral displacement a light beam having a second polarization direction orthogonal to the first polarization direction;
- wherein light propagating through the birefringent translating unit along one of the second and third light paths is laterally displaced and light propagating through the birefringent translating unit along the other of the second and third light paths is not laterally displaced, and light propagating along the third and fourth paths is combined into a single output path in the birefringent splitting and combining element.
3 more elements
An optical circulator, comprising:
- a birefringent splitting and combining element configured to split a beam of light propagating in a forward direction from a first port into first and second light paths having mutually orthogonal polarizations;
- an inverting reflector configured to reflect light travelling forward along the first light path to travel in a reverse direction along a third light path parallel to the first light path, and to reflect light travelling forward along the second light path into a reverse direction along a fourth light path parallel to the second light path,
- a first non-reciprocal polarization rotator configured to rotate polarization directions of light propagating along the first, second, third and fourth light paths by approximately 45.degree.;
- and
- a birefringent translation unit between the birefringent splitting and combining element and the inverting reflector, having a first birefringent translating element disposed in the second and third light paths configured to laterally displace a light beam propagating therethrough having a first polarization direction, and to transmit, without lateral displacement, a light beam propagating therethrough having a second polarization direction orthogonal to the first polarization direction, and having a non-birefringent element disposed in the first and fourth light paths;
- wherein light propagating along the third and fourth paths is combined into a single output path in the birefringent splitting and combining element, the single output path being coupled to a second port.
3 more elements
An optical circulator, comprising:
- a birefringent splitting and combining element configured to split a beam of light propagating in a forward direction into first and second light paths having mutually orthogonal polarizations;
- a non-reciprocal polarization rotator configured to rotate polarization directions of light propagating along the first and second light paths from the splitting and combining element by approximately 45.degree.;
- a birefringent translating unit having upper and lower portions, the first light path passing through the lower portion and the second light path passing through the upper portion;
- and
- an inverting reflector configured to reflect light travelling forward from the lower portion to travel backward through the upper portion and to reflect light travelling forward form the upper portion backward through the lower portion;
- wherein one of light propagating forward and light propagating backward through the upper portion propagates through the birefringent translating unit as an extraordinary ray, and the other of the light propagating forward and the light propagating backward through the upper portion propagates through the birefringent translating unit as an ordinary ray.
3 more elements
An optical circulator, comprising:
- a birefringent splitting and combining element configured to split orthogonally polarized beams of light propagating along an element input axis into first and second light paths;
- a first non-reciprocal polarization rotator configured to rotate polarization directions of light propagating along the first and second light paths from the first splitting and combining element by approximately 45.degree. in respectively opposing directions;
- a birefringent translating element disposed along the first and second light paths and configured to laterally displace a light beam having a first polarization direction propagating therethrough and to transmit without lateral displacement a light beam having a second polarization direction orthogonal to the first polarization direction;
- a second non-reciprocal polarization rotator configured to rotate polarization directions of light propagating along the first and second light paths from the translating element by approximately 45.degree.;
- and
- a reflector configured to reflect light propagating along the first and second light paths in a reverse direction along the first and second light paths respectively.
3 more elements
An optical circulator, comprising:
- first and second light coupling modules, each light coupling module including
- a first focusing element optically couplable to output ends of respective first and second pluralities of optical fibers, and having a first focusing power selected to direct light beams from the respective plurality of optical fibers to intersect a first focusing element axis, and
- a second focusing element spaced apart from the first focusing element by a first separation distance along the first optical axis and positioned to receive the light beams from the first focusing element, the second focusing element having a second focusing power, the first separation distance being selected to parallelize the light beams received from the first focusing element;
- and
- a non-reciprocal module, including
- a first birefringent splitting and combining element configured to split an input beam of light propagating along an element input axis from the second focusing element of the first optical coupling module into orthogonally polarized first and second light paths;
- a first non-reciprocal polarization rotator configured to rotate polarization directions of light propagating along the first and second light paths from the first splitting and combining element by approximately 45.degree. in respectively opposing directions;
- a birefringent translating element disposed along the first and second light paths and configured to laterally displace a light beam having a first polarization direction propagating therethrough and to transmit without lateral displacement a light beam having a second polarization direction orthogonal to the first polarization direction;
- a second non-reciprocal polarization rotator configured to rotate electric field vectors of light propagating along the first and second light paths from the translating element by approximately 45.degree. in opposite directions;
- and
- a second birefringent splitting and combining element configured to combine light beams propagating along the first and second light paths into an output light beam directed to the second focusing element of the second optical coupling module.
8 more elements
An optical circulator, comprising:
- a birefringent splitting and combining element configured to split a beam of light propagating in a forward direction into first and second light paths having mutually orthogonal polarizations;
- a first non-reciprocal polarization rotator configured to rotate polarization directions of light propagating along the first and second light paths from the first splitting and combining element by approximately 45.degree.;
- a birefringent translating unit having first and second portions, the first portion disposed on the first beam path and configured to laterally displace a light beam propagating therethrough with a first polarization direction and to transmit without lateral displacement a light beam having a second polarization direction orthogonal to the first polarization direction, the second portion disposed on the second beam path and being non-birefringent;
- and
- a reflecting unit configured to reflect light propagating forward along the first path to propagate in a backwards direction through the second portion of the birefringent translation unit and to reflect light propagating forward along the second light path to propagate backward through the first portion of the birefringent translation unit.
2 more elements
Dependencies are inferred from the claim text.