Hybrid binary optics collimation fill optics

• US 5,229,883 A
• Filed: 10/28/1991
• Issued: 07/20/1993
• Est. Priority Date: 10/28/1991
• Status: Expired due to Term

• Current Assignee: Mcdonnell Douglas Corporation (The Boeing Co.)
• Original Assignee: Mcdonnell Douglas Corporation (The Boeing Co.)
• Inventors: Foresi, James S., Jackson, John E., Burkhart, Gordon H.
• Primary Examiner(s): Arnold, Bruce Y.
• Assistant Examiner(s): RYAN, JAY
• Application Number:
  US07/783,394
• Time in Patent Office: 631 Days
• Field of Search: 359/565, 359/566, 359/568, 359/569, 359/574, 359/575, 359/741, 359/742, 359/619, 359/623
• US Class Current: 359/569
• 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 27/0037 with diffracting elements G02B27/0056 takes precedence; holographic optical elements G02B5/32; zone systems G02B5/1876
• 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 27/0944 Diffractive optical elements, e.g. gratings, holograms gratings per se G02B5/18; holograms used as optical elements per se G02B5/32
• CPC Class Codes: G02B 27/0966 Cylindrical lenses cylindrical lenses per se G02B3/06
• CPC Class Codes: G02B 27/4211 correcting chromatic aberrations G02B27/0056, G02B27/4222, G02B27/4227 take precedence
• CPC Class Codes: G02B 3/005 arranged along a single direction only, e.g. lenticular sheets G02B3/0043 takes precedence
• CPC Class Codes: G02B 5/1876 Diffractive Fresnel lenses; Zone plates; Kinoforms G02B5/1842, G02B5/1847 take precedence; optical systems having diffractive correction means G02B27/0037; Fresnel lenses operating by refraction G02B3/08
• CPC Class Codes: G02B 5/1885 Arranged as a periodic array
• CPC Class Codes: H01S 3/005 Optical devices external to the laser cavity, specially adapted for lasers, e.g. for homogenisation of the beam or for manipulating laser pulses, e.g. pulse shaping shaping laser beam for working metal or other materials B23K26/06; optical elements, systems or apparatus in general G02B

Abstract

A cylindrical lens and a binary optical element for collimating with low optical aberrations an asymmetrically diverging input wavefront. The binary optical element is formed on a planar substrate on which a binary optical diffraction pattern is etched on the front surface thereof. The binary optical diffraction pattern is designed such that each ray of light from the diverging input light source will travel the same optical path length or vary from that optical path length by an integer multiple of the wavelength of the light in travelling from its source to its exit from the front surface of the binary optical element. A beam angle alignment element is also provided, to be utilized in conjunction with a cylindrical lens and the binary optical element, for correcting angular misalignments of diode lasers whose output wavefront has an optical axis which is either above or below the plane in which the active region is formed. The beam angle alignment element is also a planar substrate on which a binary optic diffraction pattern is etched. The binary optic diffraction pattern of the beam angle alignment elements diffracts the wavefront exiting from the binary optic element so as to align the wavefront about its optical axis. The cylindrical lens, the binary optical element, as well as the beam angle alignment element may be used in conjunction with a single diode lasing element, as well as a one dimensional or a two dimensional diode laser array.

Claims

1. An optical lens system for collimating and redistributing a divergent input light comprising:

a) a cylindrical lens wherein said lens substantially collimates the divergent input light;

b) a binary optical element, comprising a substantially planar substrate having a front surface wherein said front surface has been formed such that the optical path length traveled by each ray of divergent input light from a source of the divergent input light to a collimation plane is substantially equal; and

c) a beam angle alignment element for aligning the divergent input light about an optical axis of the input light.

2. An optical lens system as recited in claim 1 wherein the beam angle alignment element is comprised of a planar substrate having a binary optic diffractive element etched thereon.

3. An optical lens system as recited in claim 2 wherein the binary optic diffractive element is selected from the group consisting of a two-phase level structure, a four-phase level structure, an eight phase level structure, and a sixteen phase level structure.

4. An optical lens system as recited in claim 3 wherein the substantially planar front surface has a binary optic diffractive element etched thereon.

5. An optical lens system as recited in claim 3 wherein the collimation plane is positioned such that the substantially planar front surface lies within the collimation plane.

6. An optical lens system as recited in claim 3 wherein the cylindrical lens has a first planar surface and a second convex surface.

7. An optical lens system as recited in claim 3 wherein the cylindrical lens is a biconvex cylindrical lens.

8. An array of optical lens systems for collimating and redistributing an array of divergent input light sources, comprising:

a) a plurality of cylindrical lenses wherein each of said lenses substantially collimate the divergent input light source;

b) a plurality of binary optical elements, each of the binary optical elements comprising a substantially planar substrate having a front surface with a binary optic diffractive element etched thereon wherein said front surface has been formed such that the optical path length traveled by each ray of divergent input from a source of the divergent input light to a collimation plane is substantially equal, each of the binary optical elements positioned to receive a substantially collimated light beam from a corresponding cylindrical lens; and

c) an array of beam angle alignment elements, each of the beam angle alignment elements positioned to align a light beam, emitted from a corresponding binary optical element, about an optical axis of a corresponding divergent input light source.

9. An array of optical lens systems as recited in claim 8 wherein each beam angle alignment element is comprised of a planar substrate having a binary optic diffractive element etched thereon.

10. An array of optical lens systems as recited in claim 9 wherein the substantially planar front surface of each binary optical element has a binary optic diffractive element etched thereon.

11. An array of optical lens systems as recited in claim 8 wherein the binary optic diffractive element is selected from the group consisting of a two-phase level structure, a four-phase level structure, an eight phase level structure, and a sixteen phase level structure.

12. An array of optical lens systems as recited in claim 11 wherein the collimation plane is positioned such that the substantially planar front surfaces of the plurality of binary optical elements lie within the collimation plane.

13. An array of optical lens systems as recited in claim 11 wherein each cylindrical lens of the plurality of cylindrical lenses has a first planar surface and a second convex surface.

14. An array of optical lens systems as recited in claim 11 wherein the each of the plurality of cylindrical lenses is a biconvex cylindrical lens.