Method and system for correcting an optical beam
Embodiments of the present invention provide a system and method for shaping an annular focal spot pattern to allow for more efficient optical coupling to a small gauge optical fiber. An embodiment of the present invention can include an illumination source operable to transmit an optical beam along an optical path, an optical fiber, and a correcting element positioned in the optical path between the illumination source and the optical fiber, the correcting element configured to reshape the optical beam to increase an amount of light received by the optical fiber.
1. A surgical illumination apparatus, comprising:
a xenon illumination source operable to transmit an optical beam having an uneven annular focal spot;
a beam splitter configured to split the optical beam to yield a plurality of optical beams that travel along a plurality of optical paths; and
a plurality of correcting elements, each correcting element positioned in an optical path between the illumination source and an optical fiber of a plurality of optical fibers, at least two optical fibers having different gauges, each correcting element configured to reshape an optical beam from having an uneven annular focal spot to having a focal spot with a more Gaussian intensity distribution than the uneven annular focal spot, each correcting element comprising a multi-zone lens configured to shift the optical beam from an annulus to an annulus center to increase an amount of the optical beam received at the optical fiber.
2. The surgical illumination apparatus of claim 1 , wherein each correcting element comprises an axiconic lens.
3. The surgical illumination apparatus of claim 2 , wherein the axiconic lens comprises a multi-zone axicon.
4. The surgical illumination apparatus of claim 2 , wherein the axiconic lens comprises a negative axicon.
5. The surgical illumination apparatus of claim 1 , wherein each optical fiber has a diameter that is less than or equal to the diameter of a 25-gauge fiber.
6. The surgical illumination apparatus of claim 1 , wherein each correcting element comprises a Fresnel lens comprising a series of cone shaped segments.
7. The surgical illumination apparatus of claim 1 , the multi-zone lens comprising at least four zones.
8. The surgical illumination apparatus of claim 1 , the multi-zone lens comprising at least seven zones.
9. The surgical illumination apparatus of claim 1 , the multi-zone lens comprising at least four zones, a first facet tilt angle of a first zone less than a second facet tilt angle of a second zone, the first zone closer to a center of the multi-zone lens than the second zone.
10. The surgical illumination apparatus of claim 1 , the multi-zone lens comprising at least four zones, wherein a plurality of facet tilt angles of the four zones from an inner zone to an outer zone are approximately −9 degree, −6 degree, −3 degree, and 1 degree.
11. The surgical illumination apparatus of claim 1 , further comprising a coupling lens positioned in the optical path between the correcting element and the optical fiber, the coupling lens configured to focus the reshaped optical beam onto the optical fiber, the coupling lens having a focal length of less than 0.9 inches.
12. The surgical illumination apparatus of claim 1 , each correcting element custom-fit to compensate for one or more changes along its optical path.