Integrated MEMS switches for selectively coupling light in and out of a waveguide

Patent metadata

Field	Value
Publication number	US-10684420-B2
Application number	US-201916597595-A
Country	US
Kind code	B2
Filing date	Oct 9, 2019
Priority date	Dec 16, 2016
Publication date	Jun 16, 2020
Grant date	Jun 16, 2020

Abstract

A steerable optical transmit and receive terminal includes a MEMS-based N×1 optical switch network. Each optical switch in the optical switch network uses an electrostatic MEMS structure to selectively position a translatable optical grating close to or far from an optical waveguide. In the close (“ON”) position, light couples between the translatable optical grating and the optical waveguide, whereas in the far (“OFF”) position, no appreciable light couples between the translatable optical grating and the optical waveguide. The translatable optical grating is disposed at or near a surface of the optical switch network. Thus, the translatable optical grating emits light into, or receives light from, free space. The steerable optical transmit and receive terminal also includes a lens and can steer a free space optical beam in a direction determined by which port of the N×1 optical switch network is ON.

First claim

What is claimed is:

1. An optical switch network, comprising:
a common input/output port;
a plurality of N other ports;
a first waveguide optically coupled to the common input/output port;
a plurality of first binary optical switches optically coupled to the first waveguide, the plurality of first binary optical switches being disposed along the length of the first waveguide; and
a plurality of second waveguides, each second waveguide of the plurality of second waveguides being optically coupled to the first waveguide via a respective first binary optical switch of the plurality of first binary optical switches;
for each second waveguide of the plurality of second waveguides, a respective plurality of second binary optical switches optically coupled to the second waveguide of the plurality of second waveguides, each plurality of second binary optical switches being disposed along the length of the respective second waveguide, wherein each second binary optical switch of the plurality of second binary optical switches is optically coupled between the respective second waveguide of the plurality of second waveguides and a respective port of the plurality of N other ports and comprises:
a translatable optical grating configured to translate between at least two positions, a first position of the at least two positions being sufficiently close to the respective second waveguide to optically couple with the second waveguide with a coupling efficiency of at least about 25%, and a second position of the at least two positions being sufficiently far from the respective second waveguide to optically couple with the second waveguide with a coupling efficiency of at most about 5%; and
a MEMS structure configured to selectively translate the translatable optical grating to the first position and to the second position:
wherein each second binary optical switch of the plurality of second binary optical switches is configured, when the second binary optical switch is in the first position, to optically couple between the respective second waveguide and free space beyond the planar surface.

2. The optical switch network of claim 1 , wherein the N other ports are arranged in a rectangular array.

3. The optical switch network of claim 1 , wherein the N other ports are disposed on a planar surface.

4. The optical switch network of claim 1 , further comprising:
a row-and-column addressing matrix having a plurality of rows and a plurality of columns; wherein:
each first binary optical switch of the plurality of first binary optical switches and each second binary optical switch of the plurality of second binary optical switches is:
coupled to a row of the plurality of rows;
coupled to a column of the plurality of columns; and
configured to actuate in response to signals being present on both the row of the plurality of rows and the column of the plurality of columns.

5. The optical switch network of claim 1 , wherein the optical switch network comprises a photonic chip.

6. The optical switch network of claim 1 , wherein each port of the N other ports comprises an optical coupler.

7. An optical send/receive terminal, comprising:
a lens having a field of view;
an optical switch network, the optical switch network comprising:
a common input/output port;
a plurality of N other ports optically coupled to the lens, such that each port of the plurality of N other ports is optically coupled to a unique portion of the lens field of view;
a first waveguide optically coupled to the common input/output port;
a plurality of first binary optical switches optically coupled to the first waveguide, the plurality of first binary optical switches being disposed along the length of the first waveguide;
a plurality of second waveguides, each second waveguide of the plurality of second waveguides being optically coupled to the first waveguide via a respective first binary optical switch of the plurality of first binary optical switches;
for each second waveguide of the plurality of second waveguides, a respective plurality of second binary optical switches optically coupled to the second waveguide of the plurality of second waveguides, each plurality of second binary optical switches being disposed along the length of the respective second waveguide, wherein each second binary optical switch of the plurality of second binary optical switches is optically coupled between the respective second waveguide of the plurality of second waveguides and a respective port of the plurality of N other ports and comprises:
a translatable optical grating configured to translate between at least two positions, a first position of the at least two positions being sufficiently close to the respective second waveguide to optically couple with the second waveguide with a coupling efficiency of at least about 25%, and a second position of the at least two positions being sufficiently far from the respective second waveguide to optically couple with the second waveguide with a coupling efficiency of at most about 5%; and
a MEMS structure configured to selectively translate the translatable optical grating to the first position and to the second position; and
an optical transmitter and/or an optical receiver optically coupled to the common input/output port of the optical switch network;
wherein the optical switch network defines a surface and each second binary optical switch of the plurality of second binary optical switches is configured, when the second binary optical switch is in the first position, to optically couple between the respective second waveguide and free space beyond the surface of the optical switch network.

8. The optical send/receive terminal of claim 7 , further comprising a plurality of optical fibers optically coupling the N other ports to the lens.

9. The optical send/receive terminal of claim 7 , wherein each translatable optical grating comprises a respective MEMS structure.

10. The optical send/receive terminal of claim 7 , wherein each first binary optical switch of the plurality of first binary optical switches comprises a respective MEMS structure.

11. The optical send/receive terminal of claim 7 , further comprising:
a row-and-column addressing matrix having a plurality of rows and a plurality of columns; wherein:
each first binary optical switch of the plurality of first binary optical switches and each second binary optical switch of the plurality of second binary optical switches is:
coupled to a row of the plurality of rows;
coupled to a column of the plurality of columns; and
configured to actuate in response to signals being present on both the row of the plurality of rows and the column of the plurality of columns.

12. An optical terminal, comprising:
a lens having a field of view;
and a planar optical switch that defines a plane and comprising a plurality of optical switch arrays, each optical switch array of the plurality of optical switch arrays comprising:
a common port;
a plurality of N other ports optically coupled, via free space beyond the plane of the planar optical switch, to the lens, such that each port of the plurality of N other ports is optically coupled to a unique portion of the lens field of view;
a planar N×l optical switch network optically coupled between the common port and the plurality of N other ports; and
an optical receiver optically coupled to the common port.

13. The optical terminal of claim 12 , wherein each optical switch array of the plurality of optical switch arrays further comprises an optical transmitter optically coupled to the common port.

14. The optical terminal of claim 12

Assignees

• Charles Stark Draper Laboratory Inc

Inventors

• Spector Steven J
• Moebius Michael G
• Lane Benjamin F
• Favalora Gregg E

Classifications

• G02B6/3524

  the optical element being refractive · CPC title

• H04J14/022

  For interconnection of WDM optical networks · CPC title

• G02B2006/12145

  Switch · CPC title

• G02B26/007

  the movable or deformable optical element controlling the colour, i.e. a spectral characteristic, of the light · CPC title

• G02B6/3548 Primary

  1xN switch, i.e. one input and a selectable single output of N possible outputs · CPC title