US 5,724,165 AGranted

Fault-tolerant optical routing switch

AssigneeMacro-Vision Communications, L.L.C.

InventorKuang-Yi Wu

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Abstract

An electromagnetically controlled optical switch having a plurality of optical inputs. An optical signal at each input is spatially decomposed into two coparallel, orthogonally polarized beams by a birefringent element. An array of field-controlled polarization rotators are positioned in the paths of the decomposed light beams so that the polarization of the emergent beam pairs are set to be at one of the orthogonal states (i.e., both beams are either vertical or horizontally polarized). A following birefringent element spatially routes the light beam pairs based upon their polarization. A second array of polarization rotators follows the second birefringent element and is set to be in the opposite state from the first array, such that the emergent beams are orthogonal to their input states before they entered the first polarization rotator. The beams are combined by a birefringent element to form a plurality of combined beams that are coupled to output ports.

Claims18

Dependent claims

A method for switching optical signals between either of two control states comprising the steps of:

providing an first input/output (I/O) port;
providing a second I/O port;
providing a third I/O port;
providing a fourth I/O port;
spatially decomposing an optical signal received from the first I/O port into two portions having orthogonal polarizations with respect to each other;
spatially decomposing an optical signal received from the fourth I/O port into third and fourth portions having orthogonal polarizations with respect to each other;
rotating the polarization of one of said first and second portions to match the polarization of the other of said first and second portions determined by the control state;
rotating the polarization of one of said third and fourth portions to match the polarization of the other of said third and fourth portions determined by the control state;
spatially routing the first and second portions based upon their polarization;
spatially routing the third and fourth portions based upon their polarization, wherein the polarization of the first, second, third, and fourth portions is the same before the steps of spatially routing;
rotating the polarization of one of said first and second portions to be orthogonal to the polarization of the other of said first and second portions;
rotating the polarization of one of said third and fourth portions to be orthogonal to the polarization of the other of said third and fourth portions;
passing the first and second portions through a birefringent element to recombine the first and second portions into a single optical signal aligned with one of the second and third I/O ports;
and
passing the third and fourth portions through the birefringent element to recombine the third and fourth portions into a single optical signal aligned with one of the second and third I/O ports.

12 more elements

An optical switch comprising:

a first input/output (I/O) port;
a first birefringent element having one side coupled to the first I/O port and another side defining first and second light paths;
a first polarization rotator coupled to the other side of the first birefringent element and having a first state of two possible control states, the first rotator being aligned with the first light path;
a second polarization rotator coupled to the other side of the first birefringent element and having the second state of two possible control states, the second rotator being aligned with the second light path;
a second birefringent element having one side coupled to the first and second polarization rotators;
a third polarization rotator coupled to the other side of the second birefringent element and having the second state, the third rotator being aligned with the first light path;
a fourth polarization rotator coupled to the other side of the second birefringent element and having the first state, the fourth rotator being aligned with the second light path;
and
a third birefringent element having one side coupled to the third and fourth polarization rotators and another side coupled to the second I/O port.

6 more elements

A double pole, double throw (DPDT) optical switch having two control states comprising:

a first input;
a second input;
a first birefringent element coupled to the first and second inputs, the birefringent element decomposing optical signals on each of the first and second inputs into a spatially distributed horizontally polarized component and a vertically polarized component;
a first polarization rotator array for converting the signal components from the first birefringent element into a single selected polarization determined by the control state;
a second birefringent element routing the optical signals dependent upon their polarization;
a beam splitter having a reflective surface positioned to reflect only one part of the optical signals emitted from the second birefringent element;
a prism positioned to receive the reflected signals from the beam splitter and further reflect the signals;
a second polarization rotator array receiving the reflected signals and the signals from the prism and the un-reflected signals from the beam splitter, the second polarization rotator arranged such that each emitted signal is orthogonally polarized with respect to its polarization upon entering the first polarization rotator array;
a third birefringent element receiving the signals from the second polarization rotator array and combining the signals into first and second output signals;
a first output port receiving the first output signal;
and
a second output port receiving the second output signal.

9 more elements

Dependencies are inferred from the claim text.