Infra-red light source including a raman shifter

• US 7,433,116 B1
• Filed: 03/30/2004
• Issued: 10/07/2008
• Est. Priority Date: 09/03/2002
• Status: Active Grant

• Current Assignee: Omni Continuum LLC
• Original Assignee: Cheetah Omni LLC
• Inventors: Islam, Mohammed N.
• Primary Examiner(s): Hellner; Mark
• Application Number:
  US10/812,608
• Time in Patent Office: 1,652 Days
• Field of Search: 359/333, 359/334, 372/6
• US Class Current: 359/333
• CPC Class Codes: A61B 1/0004 for electronic operation
• CPC Class Codes: A61B 1/00042 for mechanical operation
• CPC Class Codes: A61B 2505/05 Surgical care
• CPC Class Codes: A61B 34/70 Manipulators specially adapted for use in surgery
• CPC Class Codes: A61B 5/0013 Medical image data A61B1/00011, A61B6/56, A61B8/56 take precedence
• CPC Class Codes: A61B 5/0022 Monitoring a patient using a global network, e.g. telephone networks, internet
• CPC Class Codes: A61B 5/0075 by spectroscopy, i.e. measuring spectra, e.g. Raman spectroscopy, infrared absorption spectroscopy A61B5/0071 takes precedence
• CPC Class Codes: A61B 5/0084 for introduction into the body, e.g. by catheters A61B5/1459 takes precedence
• CPC Class Codes: A61B 5/02042 Determining blood loss or bleeding, e.g. during a surgical procedure
• CPC Class Codes: A61B 5/021 Measuring pressure in heart or blood vessels A61B5/0205 takes precedence
• CPC Class Codes: A61B 5/024 Detecting, measuring or recording pulse rate or heart rate A61B5/0205, A61B5/021 take precedence
• CPC Class Codes: A61B 5/06 Devices, other than using radiation, for detecting or locating foreign bodies for removing same A61B17/50 ; determining position of probes within or on the body of the patient
• CPC Class Codes: A61B 5/1455 using optical sensors, e.g. spectral photometrical oximeters
• CPC Class Codes: A61B 5/14551 for measuring blood gases
• CPC Class Codes: A61B 5/7264 Classification of physiological signals or data, e.g. using neural networks, statistical classifiers, expert systems or fuzzy systems neural networks per se G06N3/00; expert systems per se G06N5/00
• CPC Class Codes: A61B 5/742 using visual displays A61B5/339 takes precedence
• CPC Class Codes: A61B 5/7435 Displaying user selection data, e.g. icons in a graphical user interface
• CPC Class Codes: A61B 5/7445 Display arrangements, e.g. multiple display units
• CPC Class Codes: A61B 5/749 Voice-controlled interfaces
• CPC Class Codes: G16Z 99/00 Subject matter not provided for in other main groups of this subclass
• CPC Class Codes: H01S 3/302 : in an optical fibre

Abstract

An infrared light source includes one or more combiners that are coupled to at least a first pump laser and a second pump laser. The combiners are operable to couple a first optical signal generated by the first pump laser and a second optical signal generated by the second pump laser to a gain fiber, the gain fiber comprising a first waveguide structure. The light source also includes a Raman wavelength shifter that is coupled to the gain fiber. The Raman wavelength shifter being operable to wavelength shift based at least in part on a Raman effect. At least a portion of the Raman wavelength shifter comprising an intermediate waveguide structure that is coupled to a second waveguide structure capable of wavelength shifting at least one wavelength of the first optical signal to an intermediate wavelength in the intermediate waveguide structure and then a longer signal wavelength in the second waveguide structure.

Claims

1. An infrared light source, comprising:

one or more combiners coupled to at least a first pump laser operable to generate a first pump signal and a second pump laser operable to generate a second pump signal, the one or more combiners operable to combine the first pump signal and the second pump signal into a first optical signal, the first pump signal comprising at least a first wavelength and the second pump signal comprising at least a second wavelength, wherein the first wavelength of the first pump signal is substantially different than the second wavelength of the second pump signal; and

a wavelength shifter coupled to the one or more combiners, the wavelength shifter comprising a first waveguide structure and a second waveguide structure, the wavelength shifter operable to receive the first optical signal and to wavelength shift at least a portion of the first optical signal based at least in part on a Raman effect, wherein the wavelength shifter operates to wavelength shift at least the first wavelength to an intermediate optical wavelength in the first waveguide structure and to wavelength shift the intermediate optical wavelength to a longer optical wavelength in the second waveguide structure;

wherein at least a portion of the intermediate optical wavelength is greater than the first wavelength and wherein at least a portion of the longer optical wavelength is greater than the intermediate optical wavelength; and

wherein the first waveguide structure is substantially different than the second waveguide structure.

2. The infrared light source of claim 1, wherein the first pump laser is selected from the group consisting of a continuous wave laser and a pulsed laser.

3. The infrared light source of claim 1, wherein the first pump laser is selected from the group consisting of a solid state laser, a Nd:

YAG laser, a Nd;

YLF laser, laser diodes, a semiconductor laser, and a cladding pump fiber.

4. The infrared light source of claim 1, wherein the second pump laser is selected from the group consisting of a solid state laser, a Nd:

YAG laser, a Nd;

YLF laser, laser diodes, a semiconductor laser, and a cladding pump fiber.

5. The infrared light source of claim 1, wherein the second pump laser comprises a plurality of laser diodes capable of generating a plurality of pump signals substantially centered on a selected wavelength.

6. The infrared light source of claim 5, wherein the second pump laser further comprises a multiplexer capable of combining the plurality of pump signals into the second pump signal.

7. The infrared light source of claim 6, wherein the multiplexer is selected from the group consisting of a wavelength division multiplexer, a polarization multiplexer, and a power combiner.

8. The infrared light source of claim 1, wherein the second wavelength of the second pump signal is selected from the group consisting of 980 nm, 1310 nm, 1390 nm, 1400-1499 nm, and 1510 nm.

9. The infrared light source of claim 1, wherein the longer optical wavelength comprises a pulsed optical signal having a pulse repetition rate in the range of two (2) hertz to one hundred (100) megahertz.

10. The infrared light source of claim 1, wherein the longer optical wavelength comprises a pulsed optical signal having a pulse width in the range of two (2) nanoseconds to one hundred (100) milliseconds.

11. The infrared light source of claim 1, wherein a variation of the first wavelength of the first pump signal causes a variation in the longer optical wavelength.

12. The infrared light source of claim 1, wherein the one or more combiners are selected from the group consisting of a wavelength division multiplexer and a power coupler.

13. The infrared light source of claim 1, wherein the first waveguide structure is selected from the group consisting of a dispersion compensating fiber, a dispersion shifted fiber, a single mode fiber, a chalcogenide fiber, and a fused silica optical fiber.

14. The infrared light source of claim 1, wherein at least a portion of the first waveguide structure is selected from the group consisting of an optical fiber, a hollow tube waveguide, an air core waveguide, and a planar waveguide.

15. The infrared light source of claim 1, wherein the first waveguide structure at least partially contributes to increasing an optical energy of at least a portion of the first optical signal and wherein the increased optical signal energy is communicated from the first waveguide structure at a selected wavelength.

16. The infrared light source of claim 1, wherein at least a portion of the second waveguide structure is selected from the group consisting of an optical fiber, a hollow tube waveguide, an air core waveguide, and a planar waveguide.

17. The infrared light source of claim 1, wherein at least a portion of the second waveguide structure comprises an optical fiber, wherein the optical fiber is selected from the group consisting of a mid-infrared optical fiber, a chalcogenide fiber and a ZBLAN fiber.

18. The infrared light source of claim 1, wherein at least a portion of the second waveguide structure is an optical waveguide comprising a material selected from the group consisting of ZBLAN, sulfide, selenide, and telluride.

19. The infrared light source of claim 1, wherein the longer optical wavelength comprises a wavelength of approximately 1.7 microns or more.

20. The infrared light source of claim 1, wherein the longer optical wavelength comprises a wavelength in the range of two (2) microns to ten (10) microns.

21. The infrared light source of claim 1, wherein the longer optical wavelength comprises a wavelength in the range of five (5) microns to seven (7) microns.

22. The infrared light source of claim 1, further comprising a wavelength separator coupled to the wavelength shifter and capable of transmitting at least a portion of a selected wavelength from the wavelength shifter.

23. The infrared light source of claim 22, wherein the wavelength separator is selected from the group consisting of a demultiplexer, one or more partially transmissive gratings, one or more partially transmitting mirrors, one or more Fabry Perot filters and one or more dielectric gratings.

24. The infrared light source of claim 1, further comprising at least a third waveguide structure coupled to the wavelength shifter, wherein a coupling loss between the third waveguide structure and the wavelength shifter comprises no more than five (5) decibels.

36. The infrared light source of claim 1, wherein the longer optical wavelength is adapted for use in a diagnostic procedure to detect tissue abnormalities.

37. The infrared light source of claim 1, wherein the longer optical wavelength is further coupled to a medical device adapted for insertion into a patient'"'"'s body through an orifice in the body.

38. The infrared light source of claim 1, wherein the longer optical wavelength is adapted for use to ablate tissue with reduced collateral damage.

39. The infrared light source of claim 1, wherein the longer optical wavelength is adapted for use in a differential spectroscopic measurement based at least in part on a comparison of measurements taken from different portions of a sample.

40. The infrared light source of claim 1, wherein the longer optical wavelength is adapted for use in a measurement based at least in part on a comparison of a plurality of wavelengths transmitted through a sample.

25. A method of shifting an optical wavelength to a longer optical wavelength, comprising:

combining a first pump signal generated by a first pump laser and a second pump signal generated by a second pump laser into a first optical signal, the first pump signal comprising at least a first wavelength and the second pump signal comprising at least a second wavelength, wherein the first wavelength of the first pump signal is substantially different than the second wavelength of the second pump signal;

receiving the first optical signal at a wavelength shifter, the wavelength shifter comprising a first waveguide structure and a second waveguide structure, wherein the first waveguide structure is substantially different than the second waveguide structure;

shifting at least the first wavelength to an intermediate optical wavelength using the first waveguide structure based at least in part on a Raman effect;

shifting the intermediate optical wavelength to a longer optical wavelength using the second waveguide structure; and

wherein at least a portion of the intermediate optical wavelength is greater than the first wavelength and wherein at least a portion of the longer optical wavelength is greater than the intermediate optical wavelength.

26. The method of claim 25, wherein the second pump laser comprises a plurality of laser diodes capable of generating a plurality of pump signals substantially centered on a selected wavelength.

27. The method of claim 26, wherein the second pump laser further comprises a multiplexer capable of combining the plurality of pump signals into the second pump signal.

28. The method of claim 25, wherein the second wavelength of the second pump signal is selected from the group consisting of 980 nm, 1310 nm, 1390 nm, 1400-1499 nm and 1510 nm.

29. The method of claim 25, wherein the first waveguide structure at least partially contributes to increasing an optical energy of at least a portion of the first optical signal and wherein the increased optical signal energy is communicated from the first waveguide structure at a selected wavelength.

30. The method of claim 25, wherein the longer optical wavelength comprises a wavelength of approximately 1.7 microns or more.

31. The method of claim 25, wherein the longer optical wavelength comprises a wavelength in the range of two (2) microns to ten (10) microns.

32. The method of claim 25, further comprising transmitting at least a portion of a selected wavelength from the wavelength shifter into a third waveguide structure.

33. The method of claim 25, wherein the first waveguide structure is selected from the group consisting of a dispersion compensating fiber, a dispersion shifted fiber, a single mode fiber, a chalcogenide fiber, and a fused silica optical fiber.

34. The method of claim 25, wherein the second waveguide structure is selected from the group consisting of a chalcogenide fiber and a ZBLAN fiber.

35. The method of claim 25, wherein at least a portion of the second waveguide structure is an optical waveguide comprising a material selected from the group consisting of ZBLAN, sulfide, selenide, and telluride.

41. The method of claim 25, wherein the longer optical wavelength is adapted for use in a diagnostic procedure to detect tissue abnormalities.

42. The method of claim 25, wherein the longer optical wavelength is further coupled to a medical device adapted for insertion into a patient'"'"'s body through an orifice in the body.

43. The method of claim 25, wherein the longer optical wavelength is adapted for use to ablate tissue with reduced collateral damage.

44. The method of claim 25 wherein the longer optical wavelength is adapted for use in a differential spectroscopic measurement based at least in part on a comparison of measurements taken from different portions of a sample.

45. The method of claim 25, wherein the longer optical wavelength is adapted for use in a measurement based at least in part on a comparison of a plurality of wavelengths transmitted through a sample.