Method and system for generating mid-infrared light

• US 20060245461A1
• Filed: 01/20/2006
• Published: 11/02/2006
• Est. Priority Date: 01/21/2005
• Status: Abandoned Application

• Current Assignee: Omni Sciences Incorporated
• Original Assignee: Omni Services, Inc.
• Inventors: Islam, Mohammed N.
• Application Number:
  US11/335,997
• Publication Number:
  US 20060245461A1
• Time in Patent Office: Days
• US Class Current: 372/75
• CPC Class Codes: H01S 2301/02 ASE (amplified spontaneous emission), noise; Reduction thereof
• CPC Class Codes: H01S 3/094003 the pumped medium being a fibre
• CPC Class Codes: H01S 3/094046 of a Raman fibre laser
• CPC Class Codes: H01S 3/171 chalcogenide glass
• CPC Class Codes: H01S 3/302 in an optical fibre

Abstract

A mid-infrared light source comprises a pump laser, a fiber stage, and a waveguide stage. The pump laser generates light having an input wavelength between approximately one to two microns. The fiber stage comprises one or more intermediate fibers, and shifts at least a portion of the input wavelength to an intermediate wavelength longer than the input wavelength. The waveguide stage comprises one or more mid-infrared waveguides, and shifts at least a portion of the intermediate wavelength to yield mid-infrared light. The mid-infrared light has a spectrum, where at least a portion of the spectrum is approximately two microns or longer.

Claims

1. A mid-infrared light source, comprising:

a pump laser operable to;

generate light having an input wavelength, the input wavelength between approximately one to two microns;

a fiber stage coupled to the pump laser, the fiber stage comprising one or more intermediate fibers, the fiber stage operable to;

shift at least a portion of the input wavelength to an intermediate wavelength, the intermediate wavelength longer than the input wavelength; and

a waveguide stage coupled to the fiber stage, the waveguide stage comprising one or more mid-infrared waveguides, the waveguide stage operable to;

shift at least a portion of the intermediate wavelength to yield mid-infrared light, the mid-infrared light having a spectrum, at least a portion of the spectrum being approximately two microns or longer.

2. The mid-infrared light source of claim 1, wherein the pump laser comprises:

one or more laser diodes coupled to an optical amplifier.

3. The mid-infrared light source of claim 1, wherein the pump laser comprises an amplifier selected from a group consisting of:

an erbium-doped fiber amplifier, a Raman amplifier, a semiconductor amplifier, an optical parametric amplifier, and a rare-earth doped fiber amplifier.

4. The mid-infrared light source of claim 1, wherein the pump laser comprises:

a filtering system operable to reduce amplified spontaneous emission.

5. The mid-infrared light source of claim 1, wherein the pump laser comprises:

a filtering system operable to reduce amplified spontaneous emission, the filtering system comprising;

one or more wavelength filters; and

at least one temporal modulator substantially synchronized with the pump laser.

6. The mid-infrared light source of claim 1, wherein the pump laser comprises a modulated pump laser operable to:

generate the light comprising a plurality of pulses having a repetition rate, the repetition rate between one hertz to 800 megahertz.

7. The mid-infrared light source of claim 1, wherein the pump laser comprises a modulated pump laser operable to:

generate the light comprising a plurality of pulses having a temporal duration, the temporal duration approximately 100 picoseconds or longer.

8. The mid-infrared light source of claim 1, wherein the pump laser comprises a laser selected from a group consisting of:

a cladding-pumped fiber laser and a solid state laser.

9. The mid-infrared light source of claim 1, wherein at least one intermediate fiber of the one or more intermediate fibers comprises:

a resonator having one or more fiber gratings.

10. The mid-infrared light source of claim 1, wherein at least one mid-infrared waveguide of the one or more mid-infrared waveguides is selected from a group consisting of:

a chalcogenide fiber, a fluoride fiber, and a ZBLAN fiber.

11. The mid-infrared light source of claim 1, wherein at least one mid-infrared waveguide of the one or more mid-infrared waveguides is selected from a group consisting of:

a chalcogenide glass waveguide, a tellurite glass waveguide, a silicon waveguide, a tellurite fiber, a semiconductor wafer, and a semiconductor waveguide.

12. The mid-infrared light source of claim 1, wherein at least one mid-infrared waveguide of the one or more mid-infrared waveguides has a core size of approximately 30 microns or less.

13. A mid-infrared light source comprising:

a pump laser operable to;

generate light having an input wavelength, the input wavelength between approximately one to two microns;

a fiber stage coupled to the pump laser, the fiber stage comprising one or more intermediate fibers, the fiber stage operable to;

shift at least a portion of the input wavelength to an intermediate wavelength, the intermediate wavelength longer than the input wavelength; and

a waveguide stage coupled to the fiber stage, the waveguide stage comprising one or more mid-infrared fibers with a propagation loss less than approximately five decibels per meter at approximately three microns, the waveguide stage operable to;

shift at least a portion of the intermediate wavelength to yield mid-infrared light, the mid-infrared light having a spectrum, at least a portion of the spectrum being approximately two microns or longer.

14. The mid-infrared light source of claim 13, wherein at least one mid-infrared fiber of the one or more mid-infrared fibers is selected from the group consisting of:

a chalcogenide fiber, a fluoride fiber, and a ZBLAN fiber.

15. The mid-infrared light source of claim 13, wherein at least the portion of the spectrum is approximately 2.9 to 6.5 microns.

16. The mid-infrared light source of claim 13, further comprising:

an output operable to direct the mid-infrared light towards a tissue, at least the portion of the spectrum of the mid-infrared light having a wavelength where a protein absorption of the tissue exceeds a water absorption of the tissue.

17. The mid-infrared light source of claim 13, further comprising:

an output operable to direct the mid-infrared light towards a tissue, at least the portion of the spectrum of the mid-infrared light having a wavelength operable to induce a plurality of ultrasonic waves to image the tissue.

18. A method for generating mid-infrared light, comprising:

generating light having an input wavelength, the input wavelength between approximately one to two microns, the light generated at a pump laser;

shifting at least a portion of the input wavelength to an intermediate wavelength, the intermediate wavelength longer than the input wavelength, the input wavelength shifted at a fiber stage, the fiber stage comprising one or more intermediate fibers; and

shifting at least a portion of the intermediate wavelength to yield mid-infrared light, the mid-infrared light having a spectrum, at least a portion of the spectrum being approximately two microns or longer, the intermediate wavelength shifted at a waveguide stage, the waveguide stage comprising one or more mid-infrared waveguides.

19. The method of claim 18, wherein at least one mid-infrared waveguide of the one or more mid-infrared waveguides is selected from a group consisting of:

a chalcogenide fiber, a fluoride fiber, and a ZBLAN fiber.

20. The method of claim 18, wherein generating light comprising the plurality of longer pulses further comprises:

amplifying light generated by one or more laser diodes; and

filtering the amplified light to reduce amplified spontaneous emission.