Systems and methods for stabilized stimulated brillouin scattering lasers with ultra-low phase noise

• US 9,197,032 B2
• Filed: 04/02/2014
• Issued: 11/24/2015
• Est. Priority Date: 04/02/2014
• Status: Active Grant

• Current Assignee: Honeywell International Inc.
• Original Assignee: Honeywell International Inc.
• Inventors: Qiu, Tiequn, Wu, Jianfeng, Sanders, Glen A.
• Primary Examiner(s): Zhang, Yuanda
• Application Number:
  US14/243,794
• Publication Number:
  US 20150288135A1
• Time in Patent Office: 601 Days
• US Class Current: 1/1
• CPC Class Codes: G01C 19/727 using a passive ring resonator
• CPC Class Codes: H01S 3/0085 Modulating the output, i.e. the laser beam is modulated outside the laser cavity
• CPC Class Codes: H01S 3/06791 Fibre ring lasers fibre laser gyrometers G01C19/72
• CPC Class Codes: H01S 3/083 Ring lasers fibre ring lasers H01S3/06791
• CPC Class Codes: H01S 3/1053 Control by pressure or deformation
• CPC Class Codes: H01S 3/1304 by using an active reference, e.g. second laser, klystron or other standard frequency source H01S3/139 takes precedence; automatic control of electronic generators H03L7/00
• CPC Class Codes: H01S 3/1305 Feedback control systems
• CPC Class Codes: H01S 3/30 using scattering effects, e.g. stimulated Brillouin or Raman effects
• CPC Class Codes: H01S 3/302 in an optical fibre

Abstract

Systems and methods for stabilized stimulated Brillouin scattering lasers with ultra-low phase noise are provided. In one embodiment, a method for producing a Stimulated Brillouin Scattering (SBS) beam comprises: generating laser light from a tunable laser source; splitting the laser light into a first light beam and a second light beam; creating a phase modulated light beam by applying a phase modulation to the first light beam; locking a frequency of the laser light to a frequency of a ring cavity using the phase modulated light beam and a Pound-Drever-Hall servo loop coupled to the tunable laser source; coupling the second light beam into the ring cavity in a direction of travel opposite to that of the phase modulated light beam; generating a Stimulated Brillouin Scattering light beam in the ring cavity from the second light beam; and outputting the Stimulated Brillouin Scattering light beam.

Claims

1. A method for producing a Stimulated Brillouin Scattering (SBS) beam, the method comprising:

generating laser light from a tunable laser source;

splitting the laser light into a first light beam and a second light beam;

creating a phase modulated light beam by applying a phase modulation to the first light beam;

locking a frequency of the laser light to a frequency of a ring cavity using the phase modulated light beam and a Pound-Drever-Hall servo loop coupled to the tunable laser source;

coupling the second light beam into the ring cavity in a direction of travel opposite to that of the phase modulated light beam;

generating a Stimulated Brillouin Scattering light beam in the ring cavity from the second light beam; and

outputting the Stimulated Brillouin Scattering light beam;

wherein the phase modulation is applied with a phase modulator having a modulated light beam output coupled to the ring cavity via a coupler, wherein the coupler couples the modulated light beam into the ring cavity and couples out from the ring cavity the modulated light beam and the Stimulated Brillouin Scattering light beam;

wherein a wavelength division multiplexer coupled to the coupler receives the modulated light beam and the Stimulated Brillouin Scattering light beam from the coupler; and

wherein the wavelength division multiplexer directs the modulated light beam to a photo detector and directs the Stimulated Brillouin Scattering light beam to a first output.

2. The method of claim 1, wherein the power of the modulated light beam is kept below a threshold for producing a Stimulated Brillouin Scattering effect and optimized for Pound-Drever-Hall servo operation.

3. The method of claim 2, further comprising:

coupling the modulated light beam out of the ring cavity; and

directing the modulated light beam to a photo detector, wherein the photo detector converts the modulated light beam into an electrical signal.

4. The method of claim 3, wherein the phase modulation is applied at a first modulation frequency, the method further comprising:

generating a correction signal by demodulating the electrical signal at the modulation frequency; and

locking the frequency of the tunable laser light source to a resonance frequency of the ring cavity with the correction signal.

5. The method of claim 3 further comprising:

coupling a third light beam from the ring cavity, the third light beam including a first component comprising the modulated light beam and a second component comprising the Stimulated Brillouin Scattering light beam; and

separating the Stimulated Brillouin Scattering light beam from the third light beam and directing the Stimulated Brillouin Scattering light beam to an output;

separating the modulated light beam and directing it to the photo detector.

6. The method of claim 1, wherein the second light beam propagates through a second optical loop as a pump beam that is coupled into the ring cavity and travels through ring cavity in the opposite direction of the phase modulated light beam with sufficiently strong power to at least meet a threshold for producing a Stimulated Brillouin Scattering effect.

7. The method of claim 1, wherein the Stimulated Brillouin Scattering light beam is offset in frequency from the pump beam by approximately 11 GHz.

14. The apparatus of claim 1, wherein the power of the modulated light beam is kept below a threshold for producing a Stimulated Brillouin Scattering effect and optimized for Pound-Drever-Hall servo operation.

15. The apparatus of claim 1, further comprising:

a second coupler, wherein the second light beam is coupled into the ring cavity by the second coupler; and

a second wavelength division multiplexer coupled to the second coupler, wherein the second wave division multiplexer receives the modulated light beam and the Stimulated Brillouin Scattering light beam from the coupler;

wherein the wavelength division multiplexer directs the Stimulated Brillouin Scattering light beam to a second output.

8. A method for producing a Stimulated Brillouin Scattering (SBS) beam, the method comprising:

generating laser light from a tunable laser source;

splitting the laser light into a first light beam and a second light beam;

directing the first light beam to a first optical loop path that includes a ring cavity and generates a Pound-Drever-Hall (PDH) generated feedback signal back to the tunable laser source; and

directing the second light beam to a second loop path that includes the ring cavity and produces a Stimulated Brillouin Scattering (SBS) beam within the ring cavity;

wherein the first light beam and the second light beam propagate in opposite directions around the ring cavity;

wherein the first optical loop path comprises;

a phase modulator having a modulated light beam output coupled to the ring cavity via a coupler, wherein the coupler couples the modulated light beam into the ring cavity and couples out from the ring cavity the modulated light beam and the Stimulated Brillouin Scattering light beam;

a wavelength division multiplexer coupled to the coupler, wherein the wave division multiplexer receives the modulated light beam and the Stimulated Brillouin Scattering light beam from the coupler;

wherein the wavelength division multiplexer directs the modulated light beam to a photo detector and directs the Stimulated Brillouin Scattering light beam to a first output.

9. The method of claim 8, further comprising:

creating a phase modulated light beam by applying a phase modulation to the first light beam and coupling the phase modulated light beam into the ring cavity;

coupling the modulated light beam out of the ring cavity, where the power of the phase modulated light beam is kept below a threshold for producing a Stimulated Brillouin Scattering effect and optimized for Pound-Drever-Hall servo operation; and

directing the modulated light beam to a photo detector, wherein the photo detector converts the modulated light beam into an electrical signal.

10. The method of claim 9, wherein the phase modulation is applied at a first modulation frequency, the method further comprising:

generating a correction signal by demodulating the electrical signal at the modulation frequency; and

controlling the tunable laser light source with the correction signal.

11. The method of claim 10 further comprising:

coupling a third light beam from the ring cavity, the third light beam including a first component comprising the modulated light beam and a second component comprising the Stimulated Brillouin Scattering light beam;

separating the Stimulated Brillouin Scattering light beam from the third light beam and directing the Stimulated Brillouin Scattering light beam to an output; and

separating the modulated light beam and directing it to the photo detector.

12. An apparatus for producing a Stimulated Brillouin Scattering (SBS) beam, the apparatus comprising:

a tunable laser light source;

a ring cavity;

a beam splitter coupled to the tunable laser light source, the beam splitter splitting a laser beam from the tunable laser light source into a first light beam coupled to a first optical path, and a second light beam coupled to a second optical path;

wherein the first optical loop path implements a Pound-Drever-Hall (PDH) loop that generated feedback signal to lock the tunable laser source to the ring cavity;

wherein the second loop path includes the ring cavity and produces a Stimulated Brillouin Scattering (SBS) light beam within the ring cavity; and

wherein the first light beam is coupled into the ring cavity to travel around the ring cavity in a first direction and the second light beam is coupled into the ring cavity to travel around the ring cavity is a second direction opposite to the first direction;

the first optical loop path further comprising;

a phase modulator having an input coupled to the beam splitter and a modulated light beam output coupled to the ring cavity via a coupler, wherein the coupler couples the modulated light beam into the ring cavity and couples out from the ring cavity the modulated light beam and the Stimulated Brillouin Scattering light beam;

a wavelength division multiplexer coupled to the coupler, wherein the wave division multiplexer receives the modulated light beam and the Stimulated Brillouin Scattering light beam from the coupler;

wherein the wavelength division multiplexer directs the modulated light beam to the photo detector and directs the Stimulated Brillouin Scattering light beam to a first output.

13. The apparatus of claim 12, wherein the first optical loop path modulates the first light beam into a modulated light beam, couples the modulated light beam into the ring cavity, couples the modulated light beam from the ring cavity to a photo detector, where the photo detector generates an electrical signal from the modulated light beam;

the apparatus further comprising;

a servo that generates a feedback control signal from the electrical signal, the servo coupled to the tunable laser light source.

16. The apparatus of claim 12, wherein the tunable laser light source generates the laser beam so that the second light beam propagates through ring cavity with sufficiently power to produce a Stimulated Brillouin Scattering effect.

17. The apparatus of claim 12, wherein the Stimulated Brillouin Scattering light beam is offset in frequency from the second light beam by approximately 11 GHz.