Non-reciprocal acoustic devices based on linear or angular momentum biasing

Patent metadata

Field	Value
Publication number	US-9536512-B2
Application number	US-201414913240-A
Country	US
Kind code	B2
Filing date	Aug 4, 2014
Priority date	Aug 21, 2013
Publication date	Jan 3, 2017
Grant date	Jan 3, 2017

Abstract

A non-reciprocal acoustic device that accomplishes non-reciprocity via linear or angular-momentum bias. The non-reciprocal acoustic device includes an azimuthally symmetric or planar acoustical cavity (e.g., ring cavity), where the cavity is biased by imposing a circular or linear motion of a gas, a fluid or a solid medium filling the cavity. Acoustic waveguides are connected to the cavity or the cavity is excited from the surrounding medium. A port of this device is excited with an acoustic wave. When the cavity is biased appropriately, the acoustic wave is transmitted to one of the other acoustic waveguides while no transmission of the acoustic wave occurs at the other acoustic waveguides. As a result, linear non-reciprocity is now realized in acoustics without distorting the input signal or requiring high input power or bulky devices.

First claim

The invention claimed is:

1. A non-reciprocal device comprising:
an azimuthally symmetric acoustical cavity with an angular momentum bias;
a plurality of acoustic waveguides connected to said azimuthally symmetric acoustical cavity, wherein each of said plurality of acoustic waveguides is associated with an input and output port; and
an input port of a first acoustic waveguide of said plurality of acoustic waveguides is excited with an acoustic wave;
wherein said azimuthally symmetric acoustical cavity is biased in such a manner to induce total transmission of said acoustic wave to an output port of a second acoustic waveguide of said plurality of acoustic waveguides and no transmission of said acoustic wave to an output port of a third acoustic waveguide of said plurality of acoustic waveguides.

2. The non-reciprocal device as recited in claim 1 , wherein said angular momentum bias is achieved by a circular motion of a fluid filling said azimuthally symmetric acoustical cavity.

3. The non-reciprocal device as recited in claim 1 , wherein said angular momentum bias is achieved by a circular motion of a solid medium filling said azimuthally symmetric acoustical cavity.

4. The non-reciprocal device as recited in claim 1 , wherein said angular momentum bias is achieved by a circular motion of a gas filling said azimuthally symmetric acoustical cavity.

5. The non-reciprocal device as recited in claim 4 , wherein said gas comprises air.

6. The non-reciprocal device as recited in claim 1 , wherein said angular momentum bias is achieved by fans imparting a circular flow of air filling said azimuthally symmetric acoustical cavity.

7. The non-reciprocal device as recited in claim 1 , wherein said angular momentum bias is achieved by a stirrer imparting a circular flow of fluid filling said azimuthally symmetric acoustical cavity.

8. The non-reciprocal device as recited in claim 1 , wherein said angular momentum bias removes a frequency degeneracy of right and left-handed resonances of said azimuthally symmetric acoustical cavity.

9. The non-reciprocal device as recited in claim 1 , wherein said plurality of acoustic waveguides comprises three acoustic waveguides.

10. The non-reciprocal device as recited in claim 9 , wherein said three acoustic waveguides are placed at 120 degrees around said azimuthally symmetric acoustical cavity.

11. The non-reciprocal device as recited in claim 1 , wherein said non-reciprocal device has a functionality of a three-port acoustical diode.

12. The non-reciprocal device as recited in claim 1 , wherein said non-reciprocal device has a functionality of an acoustical isolator.

13. The non-reciprocal device as recited in claim 1 , wherein said azimuthally symmetric acoustical cavity is implemented in a form of a ring.

14. The non-reciprocal device as recited in claim 1 , wherein said angular momentum bias is achieved by a spatio-temporal modulation of an acoustic medium filling said azimuthally symmetric acoustical cavity.

15. A non-reciprocal device comprising:
an acoustical cavity with an angular momentum bias, wherein said acoustical cavity is composed of sub-cavities coupled to each other, wherein said angular momentum bias is achieved by a temporal modulation of acoustical properties of said sub-cavities;
a plurality of acoustic waveguides connected to said acoustical cavity, wherein each of said plurality of acoustic waveguides is associated with an input and output port; and
an input port of a first acoustic waveguide of said plurality of acoustic waveguides is excited with an acoustic wave;
wherein said acoustical cavity is biased in such a manner to induce total transmission of said acoustic wave to an output port of a second acoustic waveguide of said plurality of acoustic waveguides and no transmission of said acoustic wave to an output port of a third acoustic waveguide of said plurality of acoustic waveguides.

16. A non-reciprocal device comprising:
an acoustical cavity, wherein said acoustical cavity is composed of a planar cavity in which a linear momentum bias is applied through a transversely moving medium or a temporal modulation;
a pair of acoustic waveguides connected to said acoustical cavity, wherein each of said pair of acoustic waveguides is associated with an input and output port; and
an input port of a first acoustic waveguide of said pair of acoustic waveguides is excited with an acoustic wave;
wherein said acoustical cavity is biased in such a manner to induce total transmission of said acoustic wave excited at said input port of said first acoustic waveguide of said pair of acoustic waveguides to an output port of said second acoustic waveguide of said pair of acoustic waveguides, wherein said acoustical cavity is biased in such a manner to induce zero transmission of said acoustic wave excited at an input port of said second acoustic waveguide of said pair of acoustic waveguides to an output port of said first acoustic waveguide of said pair of acoustic waveguides.

17. A non-reciprocal device comprising:
an acoustical cavity, wherein said acoustical cavity is composed of a planar cavity in which a linear momentum bias is applied through a transversely moving medium or a temporal modulation, wherein said acoustical cavity is excited by acoustic waves propagating in free space, wherein faces of said acoustical cavity are partially-transparent in order to allow penetration of said acoustic waves into said acoustical cavity.

18. The non-reciprocal device as recited in claim 17 , wherein said acoustic waves propagate along opposite directions.

19. The non-reciprocal device as recited in claim 18 , wherein said bias is applied in such a manner as to induce total transmission for a first acoustic wave propagating along one direction and total reflection for a second acoustic wave propagating along the opposite direction.

20. The non-reciprocal device as recited in claim 17 , wherein said acoustic waves propagate along specular directions with respect to a normal direction to said faces of said acoustical cavity.

21. The non-reciprocal device as recited in claim 20 , wherein said bias is applied in such a manner as to induce transmission for a first acoustic wave propagating along one direction and total reflection for a second acoustic wave propagating along the other direction.

22. An artificial acoustic medium made of a lattice of non-reciprocal devices, wherein said acoustic medium is rendered non-reciprocal by applying angular or linear momentum bias to each element of said lattice resulting in non-reciprocal propagation for both bulk modes and edge modes of said artificial acoustic medium.

Assignees

• Univ Texas

Inventors

• Alu Andrea
• Fleury Romain
• Sounas Dimitrios

Classifications

• G10K11/04 Primary

  Acoustic filters {; Acoustic resonators} · CPC title