Optical frequency comb control

Patent metadata

Field	Value
Publication number	US-12470037-B2
Application number	US-202217807168-A
Country	US
Kind code	B2
Filing date	Jun 16, 2022
Priority date	Jun 26, 2021
Publication date	Nov 11, 2025
Grant date	Nov 11, 2025

Abstract

Optical frequency combs are used for a wide range of applications, some of which require precise control of the amplitude and phase of individual comb teeth. A technique is provided for tooth-level optical frequency comb control. A frequency comb may include a plurality of comb teeth that are separated from one another by a comb frequency spacing. This technique includes generating a train of control pulses, each of the control pulses being frequency-locked to a corresponding tooth of an optical frequency comb to be controlled. The tooth-level control of the frequency comb is enabled via stimulated Brillouin scattering using the train of control pulses.

First claim

What is claimed is:

1 . A method for optical frequency comb control, comprising:
generating a train of control pulses, each of the control pulses being frequency-locked to a corresponding tooth of an optical frequency comb to be controlled, the frequency comb having a plurality of comb teeth that are separated from one another by a comb frequency spacing; and individually modulating each comb tooth of the plurality of comb teeth via stimulated Brillouin scattering (SBS) using the train of control pulses.

2 . The method of claim 1 , wherein the providing tooth-level control comprises:
amplifying one or more teeth of the frequency comb via a Brillouin Stokes process.

3 . The method of claim 1 , wherein the providing tooth-level control comprises:
attenuating one or more teeth of the frequency comb via a Brillouin anti-Stokes process.

4 . The method of claim 1 , wherein the providing tooth-level control comprises:
phase shifting one or more teeth of the frequency comb.

5 . The method of claim 1 , wherein the providing tooth-level control comprises:
rotating a polarization of one or more teeth of the frequency comb to leverage a polarization pulling effect configured to improve extinction, thereby increasing modulation depth.

6 . The method of claim 1 , wherein the generating the train of control pulses comprises:
generating an initial control pulse; shifting a frequency of the initial control pulse by a predetermined frequency to generate a first control pulse after the initial control pulse is coupled into a recirculating fiber loop; amplifying the first control pulse to compensate for loss; repeating the shifting and amplifying steps to generate the train of control pulses, the control pulses being separated from one another by the predetermined frequency that is equal to the comb frequency spacing.

7 . The method of claim 6 , wherein the generating the train of control pulses further comprises:
fine tuning an amplitude and/or frequency of each control pulse of the train of control pulses to create a pattern that is configured to be imparted onto the frequency comb.

8 . The method of claim 1 , wherein providing tooth-level control of the optical frequency comb comprises:
coupling the train of control pulses into an SBS gain medium such that the train of control pulses propagates in a direction that is opposite of a direction of the frequency comb to allow one or more comb teeth of the frequency comb to be selectively controlled.

9 . The method of claim 8 , wherein the train of control pulses is configured to have an overall frequency offset that matches a SBS frequency of the gain medium, thereby ensuring that a particular control pulse is shifted by a Brillouin frequency away from a particular comb tooth that the particular control pulse is designed to control.

10 . The method of claim 8 , wherein the train of control pulses is configured to have a total period that is based on a time of flight of the gain medium to ensure the frequency comb interacts with at least one control pulse.

11 . The method of claim 1 , wherein generating the train of control comprises:
creating a first pulse train that comprises a predetermined number of control pulses (N) in a first stage, the control pulses being separated from one another by a predetermined frequency (Δf); and replicating the first pulse train to create a series of pulse trains separated by the predetermined number of control pulses and the predetermined frequency (NΔf) in a second stage.

12 . The method of claim 1 , wherein generating the train of control pulses comprises:
creating a first pulse train that comprises a predetermined number of control pulses (N); creating a second pulse train based on the first pulse train and coupling the second pulse train to a recirculating fiber loop while blocking the first pulse train as it recirculates with the fiber loop; and changing a frequency at which a frequency shifting element shifts to the predetermined number of control pulses and the predetermined frequency (NΔf).

13 . The method of claim 1 , wherein generating the train of control pulses comprising:
generating a plurality of pulse trains in parallel using a plurality of recirculating fiber loops; and combining the plurality of pulse trains to generate the train of control pulses.

14 . A system for optical frequency comb control, comprising:
a seed laser configured to generate an initial control pulse of a train of control pulses, each of the control pulses being frequency-locked to a corresponding tooth of an optical frequency comb to be controlled, the frequency comb having a plurality of comb teeth that are separated from one another by a comb frequency spacing; a stimulated Brillouin scattering (SBS) gain medium configured to enable tooth-level control of the frequency comb via SBS using the train of control pulses; a recirculating fiber loop configured to generate the train of control pulses, the fiber loop comprising a frequency shifting element configured to shift a frequency of the initial control pulse by a predetermined frequency to generate a first control pulse after the initial control pulse is coupled into the fiber loop; and an amplifier configured to amplify the first control pulse to compensate for loss, wherein the control pulses are separated from one another by the predetermined frequency that is equal to the comb frequency spacing.

15 . The system of claim 14 , wherein tooth-level control comprises at least one amplifying, attenuating, phase shifting one or more teeth of the frequency comb, or rotating a polarization of one or more teeth of the frequency comb.

16 . The system of claim 14 , further comprising:
a modulator configured to modulate at least one of amplitude or frequency of each control pulse of the train of control pulses to create a pattern that is configured to be imparted onto the frequency comb.

17 . The system of claim 14 , wherein the train of control pulses is coupled into the SBS gain medium such that the train of control pulses propagates in a direction that is opposite of a direction of the frequency comb to allow one or more comb teeth of the frequency comb to be selectively controlled.

18 . The system of claim 14 , wherein the train of control pulses is configured to have an overall frequency offset that matches a SBS frequency of the gain medium, thereby ensuring that a particular control pulse is shifted by a Brillouin frequency away from a particular comb tooth that the particular control pulse is designed to manipulate.

19 . The system of claim 14 , wherein the train of control pulses is configured to have a total period that is based on a time of flight of the gain medium to ensure the frequency comb interacts with at least one control pulse.

20 . A method for optical frequency comb control, comprising:
generating a train of control pulses, each of the control pulses being frequency-locked to a corresponding tooth of an optical frequency comb to be controlled, the frequency comb having a plurality of comb teeth that are separated from one another by a comb frequency spacing; and enabling tooth-level control of the frequency comb via stimulated Brillouin scattering (SBS) using the train of control pulses, wherein providing tooth-level control of the optical frequency comb comprises: coupling the train of control pulses into an SBS gain medium such that the train of control pulses propagates in a direction that is opposite of a direction of t

Assignees

• Us Gov Sec Navy

Inventors

• Redding Brandon F
• Murray Joseph Brady

Classifications

• G02F1/353 Primary

  Frequency conversion, i.e. wherein a light beam is generated with frequency components different from those of the incident light beams · CPC title

• H01S3/1106

  Mode locking · CPC title

• H01S3/1086

  using scattering effects, e.g. Raman or Brillouin effect · CPC title

• H01S3/1302

  by all-optical means, e.g. gain-clamping · CPC title

• H01S3/1307

  Stabilisation of the phase · CPC title