Crosstalk reduction in multi-channel acousto-optic modulators

Patent metadata

Field	Value
Publication number	US-2021263390-A1
Application number	US-202117150909-A
Country	US
Kind code	A1
Filing date	Jan 15, 2021
Priority date	Jan 23, 2020
Publication date	Aug 26, 2021
Grant date	—

Abstract

Aspects of the present disclosure describe techniques for controlling coherent crosstalk errors that occur in multi-channel acousto-optic modulators (AOMs) by applying cancellation tones to reduce or eliminate the crosstalk errors. For example, a method and systems are described that include applying a first radio frequency (RF) tone to generate a first acoustic wave in a first channel of the multi-channel AOM, wherein a portion of the first acoustic wave interacts with a second channel to cause a crosstalk effect, and applying a second RF tone to generate a second acoustic wave in the second channel, wherein the second acoustic wave reduces or eliminates the crosstalk effect caused by the portion of the first acoustic wave.

First claim

What is claimed is:

1 . A method of operating a multi-channel acousto-optic modulator (AOM), comprising:
applying a first radio frequency (RF) tone to generate a first acoustic wave in a first channel of the multi-channel AOM, wherein a portion of the first acoustic wave interacts with a second channel of the multi-channel AOM to cause a crosstalk effect on the second channel that is undesired; and applying a second RF tone to generate a second acoustic wave in the second channel, wherein the second acoustic wave reduces or eliminates the crosstalk effect caused by the portion of the first acoustic wave.

2 . The method of claim 1 , wherein:
the first channel includes electrical traces to which the first RF tone is applied to excite an acoustic column associated with the first acoustic wave, the second channel includes electrical traces to which the second RF tone is applied to excite an acoustic column associated with the second acoustic wave, the portion of the first RF tone interacts with the second channel by having the portion of the first RF tone coupled to the electrical traces of the second channel, and the portion of the first acoustic wave interacts with the second channel by having the acoustic columns associated with the first acoustic wave and the second acoustic wave overlap.

3 . The method of claim 1 , wherein:
applying the first RF tone turns on the first channel, and applying the second RF tone reduces or eliminates the crosstalk effect such that turning on the first channel does not cause the second channel to unintentionally be turned on by the first RF tone.

4 . The method of claim 1 , further comprising, prior to applying the second RF tone, measuring on the second channel the crosstalk effect of the portion of the first acoustic wave.

5 . The method of claim 4 , further comprising, prior to applying the second RF tone and based on the measurement of the crosstalk effect, adjusting an amplitude of the second RF tone to be smaller than and proportional to an amplitude of the first RF tone and adjusting a phase of the second RF tone to be an inverse of a phase of the crosstalk from the first RF tone.

6 . The method of claim 4 , further comprising, prior to applying the second RF tone and based on the measurement of the crosstalk effect, adjusting an amplitude of the second acoustic wave to be smaller than and proportional to an amplitude of the first acoustic wave and adjusting a phase of the second acoustic wave to be an inverse of a phase of crosstalk from the first acoustic wave.

7 . The method of claim 4 , wherein measuring the crosstalk effect further comprises measuring the crosstalk effect using a photodiode, photodetection system, an atom, or a trapped ion aligned to detect an optical beam deflected from the second channel.

8 . The method of claim 4 , wherein measuring the crosstalk effect further comprises:
transmitting an optical beam through the second channel prior to applying the first RF tone on the first channel; measuring a change in one or more optical characteristics of the optical beam in response to applying the first RF tone; and adjusting the second RF tone to minimize the change in the one or more optical characteristics of the optical beam.

9 . The method of claim 8 , wherein the one or more optical characteristics include at least one of a phase, a frequency, or an amplitude of the optical beam.

10 . The method of claim 1 , further comprising:
applying a third RF tone to generate a third acoustic wave in a third channel of the multi-channel AOM, wherein a portion of the third acoustic wave interacts with the second channel to cause an additional crosstalk effect on the second channel; and applying a fourth RF tone to generate a fourth acoustic wave in the second channel, wherein the fourth acoustic wave reduces or eliminates the crosstalk effect caused by the portion of the third acoustic wave.

11 . The method of claim 10 , wherein:
the third channel includes electrical traces to which the third RF tone is applied to excite an acoustic column associated with the third acoustic wave, the second channel includes electrical traces to which the second RF tone is applied to excite an acoustic column associated with the second acoustic wave, the portion of the third RF tone interacts with the second channel by having the portion of the third RF tone coupled to the electrical traces of the second channel, and the portion of the third acoustic wave interacts with the second channel by having the acoustic columns associated with the third acoustic wave and the second acoustic wave overlap.

12 . The method of claim 1 , wherein in addition to applying the second RF tone to reduce or eliminate the crosstalk effect on the second channel, the method further comprises applying an additional RF tone to the second channel to generate an additional acoustic wave in the second channel, wherein the additional acoustic wave is superimposed onto the second acoustic wave to control deflection of optical beams from the second channel.

13 . The method of claim 1 , wherein the first channel is immediately adjacent to the second channel in the multi-channel AOM.

14 . The method of claim 1 , wherein the first channel is not immediately adjacent to the second channel in the multi-channel AOM.

15 . A multi-channel acousto-optic modulator (AOM) system, comprising:
an AOM crystal; a first transducer disposed over the AOM crystal and associated with a first channel of the multi-channel AOM system; a second transducer disposed over the AOM crystal and associated with a second channel of the multi-channel AOM system; a first waveform generator configured to apply a first radio frequency (RF) tone to activate the first transducer to generate a first acoustic wave in the first channel, wherein a portion of the first acoustic wave interacts with the second channel to cause a crosstalk effect on the second channel; and a second waveform generator configured to apply a second RF tone to activate the second transducer to generate a second acoustic wave in the second channel, wherein the second acoustic wave reduces or eliminates the crosstalk effect caused by the portion of the first acoustic wave.

16 . The multi-channel AOM system of claim 15 , wherein:
the first transducer includes electrical traces to which the first RF tone is applied to excite an acoustic column associated with the first acoustic wave, the second transducer includes electrical traces to which the second RF tone is applied to excite an acoustic column associated with the second acoustic wave, the portion of the first RF tone interacts with the second channel by having the portion of the first RF tone coupled to the electrical traces of the second transducer, and the portion of the first acoustic wave interacts with the second channel by having the acoustic columns associated with the first acoustic wave and the second acoustic wave overlap.

17 . The multi-channel AOM system of claim 15 , further comprising a photodetector configured to measure the crosstalk effect of the portion of the first acoustic wave from an optical beam deflected from the second channel to the photodetector.

18 . The multi-channel AOM system of claim 17 , wherein the second waveform generator is further configured to adjust, prior to the application of the second RF tone and based on the measurement, the second RF tone such that an amplitude of the second RF tone is smaller than and proportional to an amplitude of the first RF tone and a phase of

Assignees

• Univ Maryland

Inventors

• Beck Kristin
• Cetina Marko
• Goldman Michael

Classifications

• B82Y10/00

  Nanotechnology for information processing, storage or transmission, e.g. quantum computing or single electron logic · CPC title

• H04B10/70

  Photonic quantum communication · CPC title

• B82Y20/00

  Nanooptics, e.g. quantum optics or photonic crystals · CPC title

• G02F1/113 Primary

  Circuit or control arrangements · CPC title

• G02F1/332 Primary

  comprising a plurality of transducers on the same crystal surface, e.g. multi-channel Bragg cell · CPC title