Optical coupling system

• US 20020025096A1
• Filed: 01/10/2001
• Published: 02/28/2002
• Est. Priority Date: 08/23/2000
• Status: Active Grant

• Current Assignee: Optton Co., Ltd.
• Original Assignee: Apollo Instruments, Inc.
• Inventors: Wang, Ying, Wang, Zhijiang, Yu, Qinyue
• Granted Patent: US 6,556,352 B2
• Time in Patent Office: Days
• US Class Current: 385/8
• CPC Class Codes: G02B 19/0014 at least one surface having optical power
• CPC Class Codes: G02B 19/0028 refractive and reflective surfaces, e.g. non-imaging catadioptric systems
• 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 27/0955 Lenses lenses per se G02B3/00
• CPC Class Codes: H01S 5/005 Optical components external to the laser cavity, specially adapted therefor, e.g. for homogenisation or merging of the beams or for manipulating laser pulses, e.g. pulse shaping H01S5/026, H01S5/18388 take precedence
• CPC Class Codes: H01S 5/4031 Edge-emitting structures

Abstract

In the present invention, the methods and apparatus for making efficient laser beam coupling are disclosed. In particular, new structures for shaping and rearranging laser beams from diode laser array are disclosed. Along with the use of unique methods for coupling pumping laser beam into optical fiber or other media, high efficiency can be achieved. These aspects of the present invention will facilitate the realization of high-efficiency and high-power fiber lasers, fiber amplifiers, or other solid state lasers. The beam shaping structures can significantly improve the quality of the beams from diode laser array, and is easy to realize and less demanding in system alignment. Thus, a diode-pumped solid state laser of this invention may comprise a laser medium, a focusing means, a beam source comprising at least one laser diode array, a beam offsetting means, an image optics and a beam redirection means.

Claims

1. An apparatus of beam shaping for laser diode array, comprising

at least one laser diode array,

beam offsetting means,

beam redirection means,

conventional optics disposed between said beam offsetting means and said beam redirection means,

wherein said beam offsetting means collimates the beams from the emitters in the fast axis and offsets said beams from each other along the fast axis by offsetting the outgoing angles of the beams, and said conventional optics collimates the beams from said beam offsetting means in the slow axis and allows each of the beams to strike upon said beam redirection means so the beams travel one or a plurality of predetermined directions after the beam redirection means.

2. An apparatus of claim 1, wherein said beam offsetting means is a cylinder-like optics that is placed in such a way that the cylindrical axis of said cylinder-like optics forms a predetermined angle with the emitter line of said laser diode array.

3. An apparatus of claim 1, wherein said beam offsetting means is a rod-like optics that is placed in such a way that the cylindrical axis of said rod-like optics forms a predetermined angle with the emitter line of said laser diode array.

4. An apparatus of claim 1, wherein said beam offsetting means comprises a collimation means and a beam offsetting prism group comprising a plurality of prisms, wherein said collimation means collimates the beams from the emitters of said laser diode array, and said prism group is made such that the collimated beam passing each prism is deflected to a different but predetermined direction.

5. An apparatus of claim 1, wherein said beam offsetting means comprises a collimation means and a beam offsetting mirror group comprising a plurality of mirrors, wherein said collimation means collimates the beams from the emitters of said laser diode array, and said mirror group is made such that the collimated beam reaching each mirror is reflected to a different but predetermined direction.

6. An apparatus of claim 1, wherein said beam offsetting means comprises a collimation means and a twisted mirror for beam offsetting, wherein said collimation means collimates the beams from the emitters of said laser diode array, and said twisted mirror is made such that the collimated beam reaching different part of said twisted mirror is reflected to a different but predetermined direction.

7. An apparatus of claim 1, wherein said beam offsetting means comprises a collimation means and a beam-deflection block for beam offsetting, wherein said collimation means collimates the beams from the emitters of said laser diode array, and said beam-deflection block is made such that the collimated beam passing each part of said beam-deflection block is refracted to a different but predetermined direction.

8. An apparatus of claim 1, wherein said beam offsetting means comprises a multi-section collimation lens placed in front of a laser diode array in which the cylinder axis of each section in the multi-section collimation lens is offset from the nearby section for a predetermined distance and is substantially parallel with the emitter line of said laser diode array.

9. An apparatus of claim 1, wherein said conventional optics is a refractive optical system.

10. An apparatus of claim 1, wherein said conventional optics is a reflective optical system.

11. An apparatus of claim 1, wherein said conventional optics is a catadioptric optical system.

12. An apparatus of claim 1, wherein the beam redirection means is a mirror group.

13. An apparatus of claim 1, wherein the beam redirection means is an optical wedge group.

14. An apparatus of claim 1, further including at least one beam focusing means

16. An apparatus of claim 15, wherein said beam offsetting means is a mirror group.

17. An apparatus of claim 15, wherein said beam offsetting means is a prism group.

19. An apparatus of claim 18, wherein said laser medium is a laser fiber with its core doped with active species.

20. An apparatus of claim 18, wherein said laser medium is a laser crystal doped with active species.

21. An apparatus of claim 18, wherein said laser medium is a laser glass doped with active species.

15. An apparatus of beam shaping for laser diode array, comprising

at least one laser diode array,

beam offsetting means,

beam redirection means,

optical system disposed between said beam offsetting means and said beam redirection means, wherein said beam offsetting means collimates the beams from the emitters in the fast axis and offsets said beams from each other along the fast axis by translation while substantially maintaining the outgoing angle of said beams and wherein said optical system collimates the beams from said beam offsetting means in the slow axis and allows each of the beams to strike upon said beam redirection means so the beams travel one or a plurality of predetermined directions after the beam redirection means.

18. A diode-pumped solid state laser apparatus comprising,

a laser medium,

at least one focusing means,

a beam source comprising at least one laser diode array along with beam redirection means, beam offsetting means for collimating the beams from the emitters of said laser diode array and offsetting the beams along the fast axis, and a conventional optics placed in such a distance from said beam offsetting means that it collimates the laser beams from said beam offsetting means in the slow axis and allows each offset beam to strike upon said beam redirection means so that the beams travel in predetermined direction after the beam redirection means,

wherein said focusing means is disposed between said beam source and the aperture of said laser medium and focuses the beam from said beam source onto the aperture of said laser medium.

22. A fiber coupled laser diode array apparatus comprising,

at least one optical fiber,

focusing means,

beam source comprising at least one laser diode array, beam offsetting means, imaging optics and beam redirection means,

wherein said beam offsetting means collimates the beams from said laser diode array and the offsets the beams from the emitters of said laser diode array along the fast axis, and said imaging optics collimates the beams in the slow axis and allows each of the offset beams to strike upon said beam redirection means so the beams travel in at least one predetermined direction after the beam redirection means, and wherein said focusing means is disposed between said beam source and the aperture of said optical fiber and focuses the beam from said beam redirection means onto the aperture of said optical fiber.