Compensated broadband fiber light source with stable mean wavelength

• US 9,683,830 B2
• Filed: 12/10/2014
• Issued: 06/20/2017
• Est. Priority Date: 10/29/2014
• Status: Active Grant

• Current Assignee: Honeywell International Inc.
• Original Assignee: Honeywell International Inc.
• Inventors: Qiu, Tiequn, Sanders, Steven J.
• Primary Examiner(s): Chowdhury, Tarifur
• Assistant Examiner(s): Rahman, Md M
• Application Number:
  US14/565,900
• Publication Number:
  US 20170082420A1
• Time in Patent Office: 923 Days
• Field of Search: 356460
• CPC Class Codes: G01B 2290/70 Using polarization in the interferometer
• CPC Class Codes: G01B 9/02007 Two or more frequencies or sources used for interferometric measurement using only beat G01B9/02003
• CPC Class Codes: G01B 9/02058 by particular optical compensation or alignment elements, e.g. dispersion compensation
• CPC Class Codes: G01C 19/72 with counter-rotating light beams in a passive ring, e.g. fibre laser gyrometers
• CPC Class Codes: G01P 3/36 Devices characterised by the use of optical means, e.g. using infrared, visible, or ultraviolet light G01P3/68 takes precedence; gyrometers using the Sagnac effect, i.e. rotation-induced shifts between counter-rotating electromagnetic beams G01C19/64
• CPC Class Codes: H01S 2301/04 Gain spectral shaping, flattening
• CPC Class Codes: H01S 3/067 Fibre lasers
• CPC Class Codes: H01S 3/06795 with superfluorescent emission, e.g. amplified spontaneous emission sources for fibre laser gyrometers fibre laser gyrometers per se G01C19/72
• CPC Class Codes: H01S 3/094003 the pumped medium being a fibre
• CPC Class Codes: H01S 3/09415 the pumping beam being parallel to the lasing mode of the pumped medium, e.g. end-pumping
• CPC Class Codes: H01S 3/13 Stabilisation of laser output parameters, e.g. frequency or amplitude
• CPC Class Codes: H01S 3/1603 rare earth
• CPC Class Codes: H01S 3/2383 Parallel arrangements

Abstract

A fiber light source comprises a laser pump configured to generate a pump laser beam at a predetermined wavelength; a first segment of rare earth doped fiber; a second segment of rare earth doped fiber; and an optical coupler coupled to a first end of the first segment and a first end of the second segment. The optical coupler is configured to split the pump laser beam based on a power coupling ratio. The first segment generates a first stimulated emission having a first mean wavelength sensitivity to pump laser power fluctuations and the second segment generates a second stimulated emission having a second mean wavelength sensitivity to pump laser power fluctuations such that a combined stimulated emission is approximately insensitive to pump laser power fluctuations.

Claims

1. A fiber light source comprising:

a pump laser configured to generate a pump laser beam at a predetermined wavelength;

a first segment of rare earth doped fiber;

a second segment of rare earth doped fiber; and

an optical coupler coupled to a first end of the first segment and a first end of the second segment, the optical coupler configured to split the pump laser beam based on a power coupling ratio such that a first portion of the pump laser beam is coupled to the first segment at a first power level and a second portion of the pump laser beam is coupled to the second segment at a second power level;

wherein the first segment of rare earth doped fiber generates a first stimulated emission having a first mean wavelength sensitivity to pump laser power fluctuations and the second segment of rare earth doped fiber generates a second stimulated emission having a second mean wavelength sensitivity to pump laser power fluctuations such that, when the first stimulated emission is combined with the second stimulated emission, a combined stimulated emission is approximately insensitive to pump laser power fluctuations.

2. The fiber light source of claim 1, wherein the first segment of rare earth doped fiber has a first length and the second segment of rare earth doped fiber has a second length different from the first length.

3. The fiber light source of claim 1, wherein the optical coupler is a first optical coupler and the power coupling ratio is a first power coupling ratio, the fiber light source further comprising a second optical coupler coupled to a second end of the first segment and to a second end of the second segment;

wherein the second optical coupler is configured to combine the first stimulated emission and the second stimulated emission based on a second power coupling ratio.

4. The fiber light source of claim 3, wherein the second power coupling ratio is different from the first power coupling ratio.

5. The fiber light source of claim 3, wherein the second coupler comprises one of a polarization beam combiner configured to combine the first stimulated emission and the second stimulated emission with different polarization states or a wavelength division multiplexer configured to combine the first stimulated emission and the second stimulated emission with different wavelengths.

6. The fiber light source of claim 1, wherein a second end of the first segment of rare earth doped fiber is coupled to a first termination fiber and the second end of the second segment of rare earth doped fiber is coupled to a second termination fiber;

wherein the optical coupler is configured to combine the first stimulated emission and the second stimulated emission based on the power coupling ratio.

7. The fiber light source of claim 6, wherein the first segment of rare earth doped fiber has a first length and the second segment of rare earth doped fiber has a second length different from the first length.

8. The fiber light source of claim 1, wherein the first segment of rare earth doped fiber and the second segment of rare earth doped fiber are doped with one of the same rare earth ions or different rare earth ions such that the first and second segments of rare earth doped fiber generate respective emissions with one of different polarization states or different wavelengths.

9. A method of reducing mean wavelength sensitivity of a fiber light source to pump power fluctuations, the method comprising:

generating a pump laser beam at a predetermined wavelength;

splitting the pump laser beam into a first portion of the pump laser beam and a second portion of the pump laser beam based on a power coupling ratio, the first portion of the pump laser beam having a first power level and the second portion of the pump laser beam having a second power level;

providing the first portion of the pump laser beam to a first segment of rare earth doped fiber, the first segment of rare earth doped fiber configured to generate a first stimulated emission having a first mean wavelength sensitivity to pump power fluctuations based on the first portion of the pump laser beam;

providing the second portion of the pump laser beam to a second segment of rare earth doped fiber, the second segment of rare earth doped fiber configured to generate a second stimulated emission having a second mean wavelength sensitivity to pump power fluctuations based on the second portion of the pump laser beam; and

combining the first stimulated emission with the second stimulated emission such that a combined stimulated emission is approximately insensitive to pump laser power fluctuations.

10. The method of claim 9, wherein splitting the pump laser beam comprises splitting the pump laser beam with a first optical coupler based on a first power coupling ratio;

and

wherein combining the first stimulated emission with the second stimulated emission comprises combining the first stimulated emission with the second stimulated emission in the first optical coupler based on the first power coupling ratio.

11. The method of claim 9, wherein splitting the pump laser beam comprises splitting the pump laser beam with a first optical coupler based on a first power coupling ratio;

and

wherein combining the first stimulated emission with the second stimulated emission comprises combining the first stimulated emission with the second stimulated emission in a second optical coupler based on a second power coupling ratio.

12. The method of claim 9, wherein at least one of the first segment of rare earth doped fiber and the second segment of rare earth doped fiber comprises an erbium doped fiber.