Wavelength selective switch WSS

Patent metadata

Field	Value
Publication number	US-12088973-B2
Application number	US-202217870014-A
Country	US
Kind code	B2
Filing date	Jul 21, 2022
Priority date	Jan 23, 2020
Publication date	Sep 10, 2024
Grant date	Sep 10, 2024

Abstract

The present disclosure provides example wavelength selective switch (WSS), wavefront control element, and integrated liquid crystal on silicon (LCoS). One example WSS includes an input port fiber array, a demultiplexing/multiplexing grating group, an output port fiber array, and a beam deflection component group including two beam deflection components and at least one wavefront control element located between the demultiplexing/multiplexing grating group and the beam deflection component group or integrated with the LCoS. At least one beam deflection component is a LCoS. The input port fiber array receives multi-wavelength optical signals. The demultiplexing/multiplexing grating group demultiplexes and outputs the multi-wavelength optical signals. The beam deflection component group deflects the multi-wavelength optical signals to the demultiplexing/multiplexing grating group. The demultiplexing/multiplexing grating group multiplexes the multi-wavelength optical signals to the output port fiber array. The wavefront control element and the LCoS jointly modulate optical signals transmitted through N*M wavelength channels.

First claim

What is claimed is:

1. A wavelength selective switch (WSS), comprising:
an input port fiber array, a demultiplexing/multiplexing grating group, an output port fiber array, and a beam deflection component group, wherein the beam deflection component group comprises two beam deflection components and at least one wavefront control element, the at least one wavefront control element comprises N*M elements of an array, and at least one beam deflection component is a liquid crystal on silicon (LCoS);
the at least one wavefront control element is located on an optical path between the demultiplexing/multiplexing grating group and the beam deflection component group, or the at least one wavefront control element and the LCOS are integrated into an integrated LCOS;
the input port fiber array comprises N ports, and the N ports receive multi-wavelength optical signals;
the demultiplexing/multiplexing grating group demultiplexes the multi-wavelength optical signals received from the N ports to N*M wavelength channels for transmission, wherein both N and M are positive integers;
the beam deflection component group deflects, to the demultiplexing/multiplexing grating group, optical signals transmitted through the N*M wavelength channels;
the demultiplexing/multiplexing grating group multiplexes, to the output port fiber array, the optical signals transmitted through the N*M wavelength channels; and
the at least one wavefront control element and the LCOS jointly modulate the optical signals transmitted through the N*M wavelength channels, wherein the WSS suppresses diffraction sub-peaks generated when the optical signals transmitted through the N*M wavelength channels pass through the LCoS.

2. The WSS according to claim 1 , wherein the N*M elements of the array are in a one-to-one correspondence with the N*M wavelength channels;
wavefront control introduced by each of the N*M elements of the array is determined based on a phase image formed by each spot unit and deflection angle of the LCOS; and
each of the N*M elements of the array modulates a corresponding optical signal in N*M optical signals received by the input port fiber array, wherein the WSS suppresses a diffraction sub-peak generated when the corresponding optical signal passes through the LCoS.

3. The WSS according to claim 2 , wherein N elements of the array that are in the N*M elements of the array and that respectively correspond to wavelength channels of a same wavelength have a same structure.

4. The WSS according to claim 2 , wherein the at least one wavefront control element is a super-surface optical element or a diffractive optical element.

5. The WSS according to claim 4 , wherein when the at least one wavefront control element is the super-surface optical element;
each of the N*M elements of the array comprises a plurality of nanopillars, a width of each nanopillar is less than or equal to a wavelength of an optical signal corresponding to the element of the array, and a height of each nanopillar is less than or equal to the wavelength of the optical signal corresponding to the element of the array;
the plurality of nanopillars are grouped and arranged in columns; and
a width occupied by each column of nanopillars is d, arrangement positions of nanopillars between adjacent columns are the same, and d is greater than or equal to a width of a nanopillar with a maximum size in the nanopillars and less than or equal to a pixel width of the LCoS.

6. The WSS according to claim 4 , wherein;
each of the N*M elements of the array comprises a plurality of nanopillars, and the plurality of nanopillars are grouped and arranged in columns; and
a center distance between adjacent nanopillars in each column of nanopillars is less than a half of the wavelength of the optical signal corresponding to the element of the array.

7. The WSS according to claim 5 , wherein when the at least one wavefront control element and the LCOS are integrated into the integrated LCOS:
the integrated LCoS comprises the super-surface optical element, a transparent electrode, an alignment layer, a liquid crystal layer, a reflective coating, a complementary metal oxide semiconductor (CMOS) substrate, and a printed circuit board (PCB) that are sequentially connected; or
the integrated LCoS comprises a glass cover, a transparent electrode, an alignment layer, a liquid crystal layer, the super-surface optical element, a spacer layer, a reflective coating, a complementary metal oxide semiconductor (CMOS) substrate, and a printed circuit board (PCB) that are sequentially connected.

8. The WSS according to claim 4 , wherein when the at least one wavefront control element is a diffractive optical element, each of the N*M elements of the array comprises a plurality of level steps of different heights, and a width of the level step is less than a wavelength of the optical signal corresponding to the element of the array.

9. The WSS according to claim 8 , wherein
a center distance between adjacent level steps in each column of level steps is less than a half of the wavelength of the optical signal corresponding to the element of the array.

10. The WSS according to claim 9 , wherein the integrated LCOS comprises the diffractive optical element, a transparent electrode, an alignment layer, a liquid crystal layer, a reflective coating, a complementary metal oxide semiconductor (CMOS) substrate, and a printed circuit board (PCB) that are sequentially connected.

11. The WSS according to claim 2 , wherein;
when an application scenario of the optical signals is facing a discrete passband, elements of the array that are in the N*M elements of the array and that correspond to wavelength channels of different wavelengths have different structures;
when the application scenario of the optical signals is a wide spectrum facing FlexGrid, elements of the array in all columns of the N*M elements of the array have a same structure; and
when the application scenario of the optical signals is an overlapped spectrum facing FlexGrid, the N*M elements of the array are grouped into R groups in columns, each group comprises S adjacent columns, elements of the array in a same group have a same structure, elements of the array in different groups have different structures, a product of R and S is equal to M, and each column of elements of the array corresponds to wavelength channels of a same wavelength that are of different ports.

12. A wavefront control element, applied to a wavelength selective switch (WSS), wherein the WSS comprises at least one liquid crystal on silicon (LCoS), and the wavefront control element comprises:
N*M elements of an array, wherein the N*M elements of the array are in a one-to-one correspondence with the N*M wavelength channels, and both N and M are positive integers;
wavefront control introduced by each of the N*M elements of the array is determined based on a phase image formed by each spot unit and deflection angle of the LCOS; and
each of the N*M array elements of the array modulates a corresponding optical signal in N*M optical signals received by an input port fiber array, wherein the WSS suppresses a diffraction sub-peak generated when the corresponding optical signal passes through the LCoS.

13. The wavefront control element according to claim 12 , wherein elements of the array that are in the N*M elements of the array and that respectively correspond to wavelength channels of a same wavelength have a same structure.

14. The wavefront control element according to claim 12 , wherein the wavefront control element is a super-surface optical element or a diffractive optical element.

Assignees

• Huawei Tech Co Ltd

Inventors

• Li Tenghao
• Wang Yong
• Xiang Hui

Classifications

• H04Q2011/0035

  using miscellaneous components, e.g. circulator, polarisation, acousto/thermo optical · CPC title

• H04Q2011/0026

  using free space propagation (e.g. lenses, mirrors) · CPC title

• H04Q2011/0016

  using wavelength multiplexing or demultiplexing · CPC title

• G02F1/31

  Digital deflection, {i.e. optical switching}(G02F1/33 takes precedence) · CPC title

• G02F1/136277

  formed on a semiconductor substrate, e.g. of silicon · CPC title