# US 11,307,354 B2 · Wavelength selective switch based on LCoS

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- Number: US 11,307,354 B2
- Document ID: US11307354B2
- Status: Granted
- Kind: B2
- Application number: 17/329,426
- Filed: 2021-05-25
- Published: 2021-09-09
- Granted: 2022-04-19
- Earliest claimed: 2018-11-26
- Assignees: Huawei Technologies Co., Ltd.
- Applicants: Huawei Technologies Co., Ltd.
- Inventors: Lei Mao; Liangjia Zong
- Web page: https://patentgrep.com/patent/US11307354B2

## CPC

- G02B 6/29304: {operating by diffraction, e.g. grating (G02B6/29301 takes precedence; spectrometers using gratings G01J3/18)}
- H04Q 11/0005: {Switch and router aspects}
- G02B 6/3524: {the optical element being refractive}
- G02B 6/354: {Switching arrangements, i.e. number of input/output ports and interconnection types}
- G02B 6/2931: {Diffractive element operating in reflection}
- G02B 6/3548: {1xN switch, i.e. one input and a selectable single output of N possible outputs}
- G02B 6/3558: {1xN switch, i.e. one input and a selectable single output of N possible outputs}
- G02B 6/356: {in an optical cross-connect device, e.g. routing and switching aspects of interconnecting different paths propagating different wavelengths to (re)configure the various input and output links (switching polarized beams G02B6/3594; power equalizers G02B6/356 and G02B6/3594; path selecting means H04Q11/0001)}
- H04Q 2011/0026: {using free space propagation (e.g. lenses, mirrors)}
- H04Q 2011/0049: {Crosstalk reduction; Noise; Power budget}
- G02B: OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- H04Q: SELECTING (switches, relays, selectors H01H; wireless communication networks H04W)

## Abstract

The technology described herein relates to a wavelength selective switch (WSS). An output port arrangement solution of an optical fiber array of the WSS includes: centers of output ports are arranged along a curve or along a combination line that includes a line segment, and a straight line connecting centers of any two output ports on the curve or the combination line does not pass through an input port. A light beam received from the input port is diffracted to the output ports through an LCoS panel, and a straight line that all diffraction orders that are generated after the diffraction pass through intersects with the curve or the line segment, and there is only one intersection point.

## Claims

### Claim 1

A wavelength selective switch (WSS), comprising:
an optical fiber array; and
a liquid crystal on silicon (LCoS) panel, wherein
the optical fiber array comprises a plurality of ports,
the plurality of ports comprise an input port and a plurality of output ports, the input port is configured to receive a light beam, the light beam is diffracted to the plurality of output ports through the LCoS panel, all diffraction orders that are generated after the diffraction are on a straight line, and the plurality of output ports are configured to obtain an order with strongest energy in all the diffraction orders, and
the plurality of output ports are arranged into one layer or a plurality of layers, and at least one layer of output ports in the one layer or the plurality of layers of output ports are arranged in the following manner:
centers of the plurality of output ports are distributed along a curve, a straight line connecting centers of any two output ports on the curve does not pass through the input port, only one intersection point exists between the straight line that all the diffraction orders pass through and the curve, a diffraction order at the intersection point is the order with strongest energy in all the diffraction orders, and one output port is arranged at the intersection point.

### Claim 2 (depends on 1)

The WSS according to claim 1, wherein the curve is a part of a circle, and the circle meets the following conditions:
an equation of the circle in a two-dimensional rectangular coordinate system is x2+y2=r2, wherein x and y represent coordinates of a point on the circle in the two-dimensional rectangular coordinate system, and r represent a constant; and
the two-dimensional rectangular coordinate system is a rectangular coordinate system centered around the input port in a plane in which the output port is located.

### Claim 3 (depends on 1)

The WSS according to claim 1, wherein the curve is a part of an ellipse, and the ellipse meets the following conditions:
an equation of the ellipse in a two-dimensional rectangular coordinate system is
x
2
a
2
+
y
2
b
2
=
1
,
wherein x and y represent coordinates of a point on the ellipse in the two-dimensional rectangular coordinate system, a and b represent constants, a is not equal to b, and both a and b are greater than 0; and
the two-dimensional rectangular coordinate system is a rectangular coordinate system centered around the input port in a plane in which the output port is located.

### Claim 4 (depends on 1)

The WSS according to claim 1, wherein
the output ports are arranged into the plurality of layers, and in the plurality of layers of output ports, one layer of output ports intersect with the straight line that all the diffraction orders pass through; and
a diffraction order at an intersection point is the order with strongest energy in all the diffraction orders, and other single-layer output ports are arranged between adjacent diffraction orders in all the diffraction orders.

### Claim 5 (depends on 1)

The WSS according to claim 1, wherein the output ports are arranged into the plurality of layers, and in the plurality of layers of output ports, arrangements of all layers of output ports are the same or different, wherein that arrangements of all layers of output ports are the same comprises the arrangements of all the layers of output ports are the same as an arrangement of other single-layer output ports, or that arrangements of all layers of output ports are different comprises an arrangement of at least one of the plurality of layers of output ports is different from an arrangement of other single-layer output ports.

### Claim 6 (depends on 4)

The WSS according to claim 4, wherein each single-layer output port in the plurality of layers of output ports does not intersect with other single-layer output ports.

### Claim 7 (depends on 5)

The WSS according to claim 5, wherein each single-layer output port in the plurality of layers of output ports does not intersect with other single-layer output ports.

### Claim 8 (depends on 1)

The WSS according to claim 1, wherein
the WSS further comprises a deflection processing component, a reflection component, a demultiplexing and multiplexing component, and a lens component, wherein the deflection processing component comprises beam deformation and deflection conversion components, the lens component comprises one lens or a combination of a plurality of lenses, and the demultiplexing and multiplexing component comprises a grating.

### Claim 9 (depends on 8)

The WSS according to claim 8, wherein
the WSS further comprises a collimator array, wherein the collimator array is located behind the optical fiber array and is configured to collimate light that is incident from the input port, and light that passes through the collimator array enters the deflection processing component.

### Claim 10 (depends on 9)

The WSS according to claim 9, wherein
a randomly polarized light beam that is incident from the collimator array is converted into linearly polarized light through the deflection processing component, and then the linearly polarized light is incident on the grating after being expanded by the lens component;
light diffracted from the grating is incident to different regions on the LCoS panel through the lens component, and light reflection directions of different wavelengths are separately controlled by controlling liquid crystal phases of the different regions on the LCoS panel; and
light output from the LCoS panel is reflected by the reflection component, passes through the lens component, the grating, and the deflection processing component, and is input to an output port of the collimator array.

### Claim 11

A wavelength selective switch (WSS), comprising:
an optical fiber array; and
a liquid crystal on silicon (LCoS) panel, wherein
the optical fiber array comprises a plurality of ports, the plurality of ports comprise one input port and a plurality of output ports, the input port is configured to receive a light beam, the light beam is diffracted to the output ports through the LCoS panel, all diffraction orders that are generated after the diffraction are on a straight line, and the plurality of output ports are configured to obtain an order with strongest energy in all the diffraction orders, and
the plurality of output ports are arranged into one layer or a plurality of layers, and at least one layer of output ports in the one layer or the plurality of layers of output ports are arranged in the following manner:
centers of the plurality of output ports are distributed along a combination line, wherein the combination line comprises a line segment, a straight line connecting centers of any two output ports on the combination line does not pass through the input port, only one intersection point exists between the straight line that all the diffraction orders pass through and the combination line, a diffraction order at the intersection point is the order with strongest energy in all the diffraction orders, and one output port is arranged at the intersection point.

### Claim 12 (depends on 11)

The WSS according to claim 11, wherein the combination line further comprises a curve connected to the line segment.

### Claim 13 (depends on 12)

The WSS according to claim 12, wherein the curve is a part of a circle, and the circle meets the following conditions:
an equation of the circle in a two-dimensional rectangular coordinate system is x2+y2=r2, wherein x and y represent coordinates of a point on the circle in the two-dimensional rectangular coordinate system, and r represent a constant; and
the two-dimensional rectangular coordinate system is a rectangular coordinate system centered around the input port in a plane in which the output port is located.

### Claim 14 (depends on 12)

The WSS according to claim 12, wherein the curve is a part of an ellipse, and the ellipse meets the following conditions:
an equation of the ellipse in a two-dimensional rectangular coordinate system is
x
2
a
2
+
y
2
b
2
=
1
,
wherein x and y represent coordinates of a point on the ellipse in the two-dimensional rectangular coordinate system, a and b represent constants, a is not equal to b, and both a and b are greater than 0; and
the two-dimensional rectangular coordinate system is a rectangular coordinate system centered around the input port in a plane in which the output port is located.

### Claim 15 (depends on 11)

The WSS according to claim 11, wherein
the output ports are arranged into the plurality of layers, and in the plurality of layers of output ports, one layer of output ports intersect with the straight line that all the diffraction orders pass through; and
a diffraction order at an intersection point is the order with strongest energy in all the diffraction orders, and other single-layer output ports are arranged between adjacent diffraction orders in all the diffraction orders.

### Claim 16 (depends on 11)

The WSS according to claim 11, wherein the output ports are arranged into the plurality of layers, and in the plurality of layers of output ports, arrangements of all layers of output ports are the same or different, wherein that arrangements of all layers of output ports are the same comprises the arrangements of all the layers of output ports are the same as an arrangement of other single-layer output ports, or that arrangements of all layers of output ports are different comprises an arrangement of at least one of the plurality of layers of output ports is different from an arrangement of other single-layer output ports.

### Claim 17 (depends on 14)

The WSS according to claim 14, wherein each single-layer output port in the plurality of output ports does not intersect with other single-layer output ports.

### Claim 18 (depends on 15)

The WSS according to claim 15, wherein each single-layer output port in the plurality of output ports does not intersect with other single-layer output ports.