Optical beam shaper and method for spatial redistribution of inhomogeneous beam

• US 6,407,870 B1
• Filed: 10/28/1999
• Issued: 06/18/2002
• Est. Priority Date: 10/28/1999
• Status: Expired due to Fees

• Current Assignee: Polametrics, Inc.
• Original Assignee: Polametrics, Inc.
• Inventors: Ritter, James, Shalapenok, Andrey, Velikov, Dimitri, Hurevich, Ihar, Shkolnik, Alexander
• Primary Examiner(s): Epps, Georgia
• Assistant Examiner(s): Lucas, Michael A.
• Application Number:
  US09/429,775
• Time in Patent Office: 964 Days
• Field of Search: 359/668, 359/642, 359/19, 359/629, 359/570, 359/618, 359/619, 359/631, 359/636
• US Class Current: 359/668
• CPC Class Codes: G02B 19/0014 at least one surface having optical power
• CPC Class Codes: G02B 19/0057 in the form of a laser diode array, e.g. laser diode bar semiconductor laser arrays with beam combining arrangement H01S5/4012
• CPC Class Codes: G02B 27/09 Beam shaping, e.g. changing the cross-sectional area, not otherwise provided for adapting the beam shape of a laser diode G02B19/0052; adapting the beam shape of an LED G02B19/0061; coupling into light guides using intermediate optical elements G02B6/4204; beam shaping specially adapted for lasers H01S3/005
• CPC Class Codes: G02B 27/0961 Lens arrays lens arrays per se G02B3/0006
• CPC Class Codes: G02B 27/0966 Cylindrical lenses cylindrical lenses per se G02B3/06

Abstract

An optical system comprising a first array of individual beam shaping elements and a second array of beam shaping elements placed between a light source, e.g., a linear array of individual laser diodes and a reshaped beam receiver, e.g., an optical fiber cable. The inhomogeneous beams emitted from the laser diodes are passed in sequence through the first and second stages so that the first stage reshaped the cross section of the beam, e.g., in the fast-axis direction and the second stage reshapes the cross section of the beam, e.g., in the slow-axis direction. As a result, the output beams of the system may have a cross section reshaped to any desired configuration, e.g., suitable for inputting into the optical fiber cable and having divergences individually adjusted in mutually perpendicular directions.

Claims

1. An optical beam shaper for spatial redistribution of inhomogeneous beams emitted from a plurality of individual coherent light sources and a reshaped beam receiver for receiving reshaped beams from said individual coherent light sources, said inhomogeneous beams having in its cross section a first direction and a second direction which is perpendicular to said first direction, beam divergences in said first direction and said second direction being different, said optical beam shaper comprising, at least:

a first beam reshaping stage having an input side and an output side, said input side of said first beam reshaping stage facing said plurality of individual coherent light sources;

a second beam reshaping stage having an input side facing said output side of said first beam reshaping stage and an output side facing said reshaped beam receiver;

said first beam reshaping stage reshaping said inhomogeneous beams in said first direction, and said second beam reshaping stage reshaping said inhomogeneous beams in said second direction;

at least one of said stages having a plurality of beam shaping elements with refractive surfaces, at least part of said inhomogeneous beams passing through at least part of said refractive surfaces, said beam shaping elements being placed in positions that prevent intersection of said inhomogeneous beams on said input side of said second stage.

2. The optical beam shaper of claim 1, wherein said beam shaping elements being made in form of a plurality of individual aspheric lenses having convex refractive surfaces on said input side facing said individual coherent light sources.

3. The optical beam shaper of claim 1, wherein said first beam shaping stage has a first array of individual beam shaping elements and said second beam shaping stage having a second array of individual beam shaping elements, at least part of said beam shaping elements of said first stage receiving at least part of individual inhomogeneous beams from said individual coherent light sources, said individual beam shaping elements of said second array receiving individual beams reshaped by said individual beam shaping elements of said first stage.

4. The optical beam shaper of claim 3, wherein said first beam shaping stage and said second beam shaping stage comprise an integral unit made of an optical material.

5. The optical beam shaper of claim 4, wherein said optical material being selected from a group consisting of quarts, glass, fused silica, and plastic.

6. The optical beam shaper of claim 1, wherein said second beam shaping stage comprises a continuous concave surface formed on said output side of said second stage.

7. The optical beam shaper of claim 1, wherein said second beam shaping stage comprises a continuous convex surface formed on said input side of said second stage.

8. An optical system, comprising:

a plurality of individual coherent light sources each of which emits inhomogeneous beams having in its cross section a first direction and a second direction perpendicular to said first direction, beam divergences in said first direction and said second direction being different;

a reshaped beam receiver for receiving reshaped beams from said individual coherent light sources; and

a beam shaper between said plurality of said individual coherent light sources and said reshaped beam receiver;

said beam shaper having a first beam reshaping stage having an input side and an output side, said input side of said first beam reshaping stage facing said plurality of individual coherent light sources;

a second beam reshaping stage having an input side facing said output side of said first beam reshaping stage and an output side facing said reshaped beam receiver;

said first beam reshaping stage reshaping said inhomogeneous beams in said first direction, and said second beam reshaping stage reshaping said inhomogeneous beams in said second direction;

at least one of said stages having a plurality of beam shaping elements with refractive surfaces, at least part of said inhomogeneous beams passing through at least part of said refractive surfaces, said beam shaping elements being placed in positions that prevent intersection of said inhomogeneous beams on said input side of said second stage.

9. The optical system of claim 8, wherein said beam shaping elements being made in form of a plurality of individual aspheric lenses having convex refractive surfaces on said input side facing said individual coherent light sources.

10. The optical beam shaper of claim 8, wherein said first beam shaping stage has a first array of individual beam shaping elements and said second beam shaping stage having a second array of individual beam shaping elements, at least part of said beam shaping elements of said first stage receiving at least part of individual inhomogeneous beams from said individual coherent light sources, said individual beam shaping elements of said second array receiving individual beams reshaped by said individual beam shaping elements of said first stage, said reshaped beam receiver receiving individual beams reshaped by said second stage.

11. The optical beam shaper of claim 10, wherein said individual beams have cross sections which fit into the boundaries of the cross section of said reshaped beam receiver.

12. The optical beam shaper of claim 11 wherein said individual light sources are laser diodes, and said reshaped beam receiver is an optical fiber cable.

13. An optical system, comprising:

a linear array of individual laser diodes each of which emits inhomogeneous beams having in its cross section a first direction and a second direction perpendicular to said first direction, a difference between beam divergences in said first direction and said second direction having a maximum value as compared to other mutually perpendicular pairs of axes in said cross section;

a reshaped beam receiver for receiving reshaped beams from said individual laser diodes; and

a beam shaper between said plurality of said individual laser diodes and said reshaped beam receiver;

said beam shaper having a first beam reshaping stage having an input side and an output side, said input side of said first beam reshaping stage facing said plurality of individual laser diodes;

a second beam reshaping stage having an input side facing said output side of said first beam reshaping stage and an output side facing said reshaped beam receiver;

said first beam reshaping stage reshaping said inhomogeneous beams in said first direction, and said second beam reshaping stage reshaping said inhomogeneous beams in said second direction;

at least one of said stages having a plurality of beam shaping elements with refractive surfaces, said inhomogeneous beams passing through said refractive surfaces, said beam shaping elements being placed in positions that prevent intersection of said inhomogeneous beams on said input side of said second stage.

14. The optical system of claim 13, wherein said beam shaping elements of said first stage and of said second stage is made in form of a plurality of individual aspheric lenses having convex refractive surfaces on the input sides of said first stage and said second stage facing said individual laser diodes.

15. The optical beam shaper of claim 14, wherein said individual beams have cross sections which fit into the boundaries of the cross section of said reshaped beam receiver.

16. The optical beam shaper of claim 15 wherein said reshaped beam receiver is an optical fiber cable.

17. A method for spatial redistribution of inhomogeneous beams emitted from a plurality of linearly arranged coherent light sources and having in their cross sections two mutually perpendicular directions in which the difference in divergences of said inhomogeneous beams has a maximum value, the method comprising the steps of:

providing a beam shaper having a first beam-shaping stage of a plurality of beam shaping elements for shaping said inhomogeneous beams in one of said directions and a second beam-shaping stage of a plurality of beam shaping elements for shaping said inhomogeneous beams in the other of said directions;

reshaping said inhomogeneous beams by passing them through said first stage of said plurality of beam shaping elements thus obtaining beams reshaped in said one of said directions;

reshaping said beams reshaped in said one of said directions by passing them through said second stage of said plurality of beam shaping elements thus obtaining beams reshaped in said other of said directions; and

directing said beams reshaped in said other of said directions to a shaped beam receiver.