# US 12,216,381 B2 · Optical quantum logic for use in large operational spaces

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- Number: US 12,216,381 B2
- Document ID: US12216381B2
- Status: Granted
- Kind: B2
- Application number: 18/313,409
- Filed: 2023-05-08
- Published: 2024-01-11
- Granted: 2025-02-04
- Earliest claimed: 2019-05-10
- Assignees: Purdue Research Foundation
- Applicants: Purdue Research Foundation
- Inventors: Andrew Weiner; Poolad Imany
- Web page: https://patentgrep.com/patent/US12216381B2

## CPC

- G02F 3/00: Optical logic elements; Optical bistable devices
- G01J 1/42: using electric radiation detectors (optical or mechanical part G01J1/04; by comparison with a reference light or electric value G01J1/10)
- G06N 10/00: Quantum computing, i.e. information processing based on quantum-mechanical phenomena
- G06N 10/20: Models of quantum computing, e.g. quantum circuits or universal quantum computers
- G06N 10/70: Quantum error correction, detection or prevention, e.g. surface codes or magic state distillation
- H04L 9/0852: {Quantum cryptography (transmission systems employing electromagnetic waves other than radio waves, e.g. light, infrared H04B10/00; wavelength-division multiplex systems H04J14/02; WDM arrangements H04J14/03)}
- H04B 10/70: Photonic quantum communication
- G02F: OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
- G01J: MEASUREMENT OF INTENSITY, VELOCITY, SPECTRAL CONTENT, POLARISATION, PHASE OR PULSE CHARACTERISTICS OF INFRARED, VISIBLE OR ULTRAVIOLET LIGHT; COLORIMETRY; RADIATION PYROMETRY (light sources F21, H01J, H01K, H05B; investigating properties of materials by optical means G01N)
- G06N: COMPUTING ARRANGEMENTS BASED ON SPECIFIC COMPUTATIONAL MODELS
- H04L: TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION (arrangements common to telegraphic and telephonic communication H04M)
- H04B: TRANSMISSION

## Abstract

A method of generating a photon with multiple dimensions includes a step of generating a first photon encoded with quantum information in each of two or more frequency bins and at least one time bin. The method further includes performing a frequency dependent time operation to entangle (i.e. make non-separable) the frequency bins and the time bins in the photon.

## Claims

### Claim 1

An optical quantum logic gate, comprising
an input configured to receive a first photon encoded with quantum information in two or more frequency bins and at least one time bin; and
an optical gate element configured to perform a frequency dependent time operation to generate non-separability between the frequency bins and at least two time bins in the first photon, and wherein a different number of time bins in the first photon can exist after the frequency dependent time operation.

### Claim 2 (depends on 1)

The optical quantum logic gate of claim 1, wherein the optical gate element further comprises:
a frequency router configured to separate at least two of the frequency bins into at least first and second spatial paths;
a time-domain logic gate configured to perform a time operation in the second spatial path; and
a combiner operably coupled to recombine the frequency bins on the at least first and second spatial paths into an output spatial path.

### Claim 3 (depends on 2)

The optical quantum logic gate of claim 2, wherein each of the frequency router and the combiner comprises a dense wavelength division multiplexer.

### Claim 4 (depends on 2)

The optical quantum logic gate of claim 2, the time-domain logic gate comprises a cyclic shift X gate.

### Claim 5 (depends on 1)

The optical quantum logic gate of claim 1, wherein the optical gate element includes a dispersion module configured to perform a group velocity dispersion to delay at least one of the frequency bins based on frequency.

### Claim 6 (depends on 5)

The optical quantum logic gate of claim 5, wherein the dispersion module comprises a chirped fiber Bragg grating to perform the group velocity dispersion.

### Claim 7 (depends on 5)

The optical quantum logic gate of claim 5, wherein the optical gate further comprises a time-domain logic gate operably coupled to the dispersion module.

### Claim 8 (depends on 1)

The optical quantum logic gate of claim 1, wherein the frequency dependent time operation comprises a frequency dependent delay.