US 6,275,312 B1Granted

Optical routing switch

AssigneeChorum Technologies LP

InventorsMichael J. Derks, Kuang-Yi Wu, Jian-Yu Liu

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Abstract

An optical routing switch employs a polarization-dependent routing (PDR) element formed by joining a plurality of prisms to form a substantially X-shaped interface between the prisms. A polarizing beam splitter (PBS) coating is applied to the interface, so that the interface transmits light having a first polarization along a transmitted optical path and reflects lights having a second, orthogonal polarization along a reflected optical path. A plurality of input/output ports are aligned to communicate optical signals along transmitted and reflected optical paths of the PDR element. Each input port has a birefringent element spatially separating the input optical signal into a pair of orthogonally-polarized beams, and a polarization rotator rotating the polarization of at least one of the pair of beams so that both beams have substantially the same polarization determined by the control state of the optical routing switch. Similarly, each output port has a polarization rotator that rotates the polarization of at least one of the pair of beams exiting the PDR element so that the beams have substantially orthogonal polarizations, and a birefringent element that combines the orthogonally-polarized beams into an output optical signal. Two PDR elements can be combined in an offset relationship to create a double ring add/drop switch or east/west protection switch.

Claims19

Dependent claims

An optical routing switch comprising:

a polarization-dependent routing element having:
(a) a plurality of prisms joined to form a substantially X-shaped interface between said prisms;
and
(b) a polarizing beam splitter (PBS) coating in said interface between said prisms, so that said interface transmits light having a first polarization along a transmitted optical path and reflects lights having a second polarization orthogonal to said first polarization along a reflected optical path;
and
a plurality of input/output (I/O) ports aligned to communicate optical signals along said transmitted and reflected optical paths of said polarization-dependent routing element;
wherein at least one of said I/O ports is an input port having:
(a) a birefringent element spatially separating an input optical signal into a pair of orthogonally-polarized beams;
(b) a polarization rotator rotating the polarization of at least one of the pair of beams so that both beams have substantially the same polarization determined by the control state of the optical routing switch;
and
wherein at least one of said I/O ports is an output port positioned to receive the pair of beams exiting said polarization-dependent routing element along one of said optical paths, said output port having:
(a) a polarization rotator rotating the polarization of at least one of the pair of beams exiting said polarization-dependent routing element so that the beams have substantially orthogonal polarizations;
and
(b) a birefringent element combining the orthogonally-polarized beams from said polarization rotator of said output port into an output optical signal;
and
wherein one of the pair of beams propagates from the input port to the output port along a first optical path having a first path length and the other of the pair of beams propagates from the input port to the output port along a second optical path having a second path length substantially similar to the first path length.

13 more elements

A 2×2 optical routing switch comprising:

a polarization-dependent routing (PDR) element having:
(a) a plurality of prisms joined to form a substantially X-shaped interface between said prisms;
and
(b) a polarizing beam splitter (PBS) coating in said interface between said prisms, so that said interface transmits light having a first polarization along a transmitted optical path and reflects lights having a second polarization orthogonal to said first polarization along a reflected optical path;
and
two input ports having:
(a) a birefringent element spatially separating an input optical signal into a pair of orthogonally-polarized beams;
and
(b) a polarization rotator rotating the polarization of at least one of the pair of beams so that both beams for each input port have substantially the same polarization determined by the control state of the optical routing switch;
and
two output ports having:
(a) a polarization rotator rotating the polarization of at least one of the pair of beams exiting said PDR element so that the beams have substantially orthogonal polarizations;
and
(b) a birefringent element combining the orthogonally-polarized beams from said polarization rotator into an output optical signal for each output port;
wherein said first output port receives the optical signal along a transmitted optical path through said PDR element from said first input port in a first control state, and receives the optical signal along a reflected optical path through said PDR element from said second input port in a second control state;
wherein said second output port receives the optical signal along a transmitted optical path through said PDR element from said second input port in the first control state, and receives the optical signal along a reflected optical path through said PDR element from said first input port in the second control state;
and
wherein one of the pair of beams propagates from an input port to an output port along a first optical path having a first path length and the other of the pair of beams propagates from an input port to an output port along a second optical path having a second path length substantially similar to the first path length.

15 more elements

An optical routing switch comprising:

at least one input port having:
(a) a birefringent element separating an input beam into a pair of orthogonally-polarized beams;
and
(b) polarization rotator selectively rotating the polarization of at least one of said pair of beams so that both beams have the same polarization determined by the control state of the optical routing switch;
a network of polarization-dependent routing (PDR) elements receiving said beams exiting said input port, wherein at least one of said PDR elements includes:
(a) a plurality of prisms joined to form a substantially X-shaped interface between said prisms;
and
(b) a polarizing beam splitter (PBS) coating in said interface between said prisms, so that said interface transmits light having a first polarization along a transmitted optical path and reflects lights having a second polarization orthogonal to said first polarization along a reflected optical path;
a plurality of output ports aligned to communicate optical signals along said transmitted and reflected optical paths of said PDR element, each output port having:
(a) polarization rotator rotating the polarization of at least one of said pair of beams so that said beams are orthogonally polarized;
and
(b) a birefringent element combining said orthogonally-polarized beams at said output port;
wherein one of the pair of beams propagates from an input port to an output port along a first optical path having a first path length and the other of the pair of beams propagates from an input port to an output port along a second optical path having a second path length substantially similar to the first path length.

10 more elements

An optical routing switch having a switching configuration determined by a specified control state, said optical routing switch comprising:

a first polarization-dependent routing (PDR) element having:
(a) a plurality of prisms joined to form a substantially X-shaped interface between said prisms;
and
(b) a polarizing beam splitter (PBS) coating in said interface between said prisms, so that said interface transmits light having a first polarization along a transmitted optical path and reflects lights having a second polarization orthogonal to said first polarization along a reflected optical path;
(c) a first port;
(d) a second port aligned to communicate with said first port along a reflected optical path through said first PDR element;
and
(e) a third port aligned to communicate with said first port along a transmitted optical path through said first PDR element;
a second PDR element having:
(a) a plurality of prisms joined to form a substantially X-shaped interface between said prisms;
and
(b) a polarizing beam splitter (PBS) coating in said interface between said prisms, so that said interface transmits light having a first polarization along a transmitted optical path and reflects lights having a second polarization orthogonal to said first polarization along a reflected optical path;
(c) a fourth port aligned to communicate with said third port along a reflected optical path through said first PDR element and said second PDR element;
(d) a fifth port aligned to communicate with said second port along a transmitted optical path through said first PDR element and said second PDR element;
and
(e) a sixth port aligned to communicate with said fourth port along a transmitted optical path through said second PDR element, and to communicate with said fifth port along a reflected optical path through said second PDR element;
wherein at least one of said ports is an input port having:
(a) a birefringent element spatially separating an input optical signal into a pair of orthogonally-polarized beams;
and
(b) a polarization rotator rotating the polarization of at least one of the pair of beams so that both beams have substantially the same polarization determined by the control state of the optical routing switch;
and
wherein at least one of said ports is an output port having:
(a) a polarization rotator rotating the polarization of at least one of the pair of beams exiting a PDR element so that the beams have substantially orthogonal polarizations;
and
(b) a birefringent element combining the orthogonally-polarized beams from said polarization rotator of said output port into an output optical signal.

22 more elements

Dependencies are inferred from the claim text.

Facts

Application: 09/416,089Filed 12 Oct 1999 · continuation in part
Priority: 2 Apr 1997
Granted: 14 Aug 2001
Term ends: Not estimatedThe source records don’t support an estimate.

Classification12 codes

G02F 1/31
For the control of the position or the direction of light beams, i.e. deflection: digital deflection, i.e. optical switching
G02B 6/272
Cascade of polarisation selective or adjusting operations: comprising polarisation means for beam splitting and combining
G02B 6/2766
Characterised by their function or use, i.e. of the complete device: manipulating the plane of polarisation from one input polarisation to another…
G02B 6/2773
Characterised by their function or use, i.e. of the complete device: polarisation splitting or combining

Family

Application60/042,575Us provisional application · filed 2 Apr 1997
Application08/979,525Parent of this continuation-in-part · filed 26 Nov 1997
Application09/063,611Parent of this continuation-in-part · filed 21 Apr 1998
US 6,049,404 AParent of this continuation-in-part
US 5,946,116 AParent of this continuation-in-part
US 6,275,312 B1This patent

From the US filing history. Foreign family members aren’t listed.