Multi-channel optical coupler for spinning catheter

1. A multi-channel optical coupler comprising:

a housing configured to spin about an axis, the housing having a proximal face and a distal face;

walls forming a central aperture on the proximal face, the central aperture intersecting the axis;

a first optical relay for guiding a first beam from the central aperture to a central port on the distal face; and

a second optical relay for guiding a second beam to a detector from an eccentric port on the distal face

wherein the first optical relay includes a stationary lens disposed to direct the first beam onto the central aperture.

2. The optical coupler of claim 1 , wherein the first optical relay further comprises a focusing lens disposed between the stationary lens and the central port.

3. The optical coupler of claim 1 , wherein the first optical relay comprises a graduated index of refraction lens seated in the central aperture, the graduated index of refraction lens being configured to direct the first beam to the central port.

4. A multi-channel optical coupler comprising:

a housing configured to spin about an axis, the housing having a proximal face and a distal face;

walls forming a central aperture on the proximal face, the central aperture intersecting the axis;

a first optical relay for guiding a first beam from the central aperture to a central port on the distal face; and

a second optical relay for guiding a second beam to a detector from an eccentric port on the distal face

wherein the second optical relay includes a collimating lens within the housing, the collimating lens being disposed to guide the second beam entering the housing at the eccentric port toward a detector mounted on an inner wall of the housing.

5. The optical coupler of claim 4 , wherein the second optical relay further comprises a light-directing element disposed to direct the second beam toward a peripheral wall of the housing.

6. A multi-channel optical coupler comprising:

a housing configured to spin about an axis, the housing having a proximal face and a distal face;

walls forming a central aperture on the proximal face, the central aperture intersecting the axis;

a first optical relay for guiding a first beam from the central aperture to a central port on the distal face; and

a second optical relay for guiding a second beam to a detector from an eccentric port on the distal face

wherein the second optical relay includes:

walls forming an eccentric aperture in the proximal face of the housing, the eccentric aperture being disposed to permit the second beam to pass therethrough; and

an annular mirror outside the housing, the annular mirror being disposed to intercept a path traced by the second beam emerging from the eccentric aperture as the housing spins.

7. The optical coupler of claim 6 , wherein the annular mirror comprises walls forming a mirror aperture disposed to permit the first beam to pass therethrough.

8. The optical coupler of claim 6 , wherein the annular mirror is disposed to direct a path traced by the second beam onto a stationary detector.

9. A multi-channel optical coupler comprising:

a housing configured to spin about an axis, the housing having a proximal face and a distal face;

walls forming a central aperture on the proximal face, the central aperture intersecting the axis;

a first optical relay for guiding a first beam from the central aperture to a central port on the distal face;

a second optical relay for guiding a second beam to a detector from an eccentric port on the distal face; and

a slip ring disposed on an outer surface of the housing, the slip ring being in electrical communication with a detector within the housing.

10. A system for identifying vulnerable plaque, the system comprising:

a catheter having a collection fiber and a delivery fiber extending therethrough; a housing configured to spin about an axis, the housing having a proximal face and a distal face, the proximal face having walls forming a central aperture and the distal face being engaged with the catheter;

a first optical relay extending between the central aperture and a central port on the distal face, the central port being in optical communication with the delivery fiber; and

a second optical relay extending between a detector and an eccentric port on the distal face, the eccentric port being in optical communication with the collection fiber.

11. The system of claim 10 , wherein the first optical relay comprises a lens disposed to receive a delivery beam passing through the central aperture and to direct the delivery beam into the central port.

12. The system of claim 10 , wherein the lens comprises a graduated index of refraction lens seated in the central aperture.

13. The system of claim 10 , wherein the second optical relay comprises a lens disposed in the housing to guide a collection beam from the eccentric port to the detector.

14. The system of claim 10 , wherein the second optical relay comprises:

walls forming an eccentric aperture in the proximal face of the housing, the eccentric aperture being disposed to permit the second beam to pass therethrough; and

an annular mirror disposed outside the housing disposed to intercept a path traced by the collection beam emerging from the eccentric aperture as the housing spins.

15. The system of claim 14 , wherein the annular mirror comprises walls forming a central aperture disposed to allow the collection beam to pass therethrough.

16. The system of claim 14 , wherein the annular mirror is disposed to direct a path traced by the collection beam onto a stationary detector.

17. The system of claim 10 , further comprising a slip ring disposed on an outer surface of the housing, the slip ring being in electrical communication with a detector within the housing.

18. A method for providing optical coupling to a collection fiber and a delivery fiber, the method comprising:

transmitting a delivery beam into a central aperture of a housing;

guiding the delivery beam from the central aperture to a central port in the housing, the central port being in optical communication with the delivery fiber;

receiving a collection beam from an eccentric port in the housing, the eccentric port being in optical communication with the collection fiber; and

guiding the collection beam to a detector by relaying the collection beam from the eccentric port to a detector within the housing.

19. The method of claim 18 , wherein guiding the delivery beam comprises relaying the delivery beam from the central aperture to the central port.

20. A method for providing optical coupling to a collection fiber and a delivery fiber, the method comprising:

transmitting a delivery beam into a central aperture of a housing;

guiding the delivery beam from the central aperture to a central port in the housing, the central Port being in optical communication with the delivery fiber;

receiving a collection beam from an eccentric port in the housing, the eccentric port being in optical communication with the collection fiber; and

guiding the collection beam to a detector by

relaying the collection beam from the eccentric port to an eccentric aperture in the housing; and

relaying the collection beam from the eccentric aperture to a detector outside the housing.

21. The method of claim 20 , wherein relaying the collection beam from the eccentric aperture to the detector comprises reflecting the collection beam off an annular mirror toward the detector.

22. The method of claim 21 , wherein guiding the delivery beam comprises passing the delivery beam through a hole in the annular mirror.