Patent US5436990A successfully refreshed from Google Patents.
US5436990A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Apparatus for coupling a multiple emitter laser diode to a multimode optical fiber
Assignee: Newport Corp USA
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Filing: 1992-02-25
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Granted: 1995-07-25
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Expires: 2012-02-25
Abstract
Abstract A small diameter multimode optical fiber with a low numerical aperture (i.e., 0.1) is used as a microlens to collimate the output emissions of a laser diode before butt coupling the output of the laser diode to an optical fiber. The optical fiber used as the microlens is chosen such that its diameter roughly equals the diameter of the fiber to be coupled to the laser diode. One end of the fiber is mounted in a fixed position and the other end of the fiber is slip fit into the end of a hollow receiving member mounted in a fixed position and running parallel to the axis of the fiber. The collimation is performed in the high NA direction of the output of the laser diode. The output of a bundle of butt coupled optical fibers may be used to pump a laser system.
Inventors
- 👤 David F. Head
- 👤 Thomas M. Baer
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-06 13:39
CPC Classifications
G; G02; G02B; G02B6/00; G02B6/24; G02B6/42; G02B6/4201; G02B6/4249; G02B6/425; G02B6/4204; G02B6/4206; H; H01; H01S; H01S3/00; H01S3/09; H01S3/091; H01S3/094; H01S3/0941; H01S3/094049; H01S3/094053; H01S5/00; H01S5/40; H01S5/4012; H01S5/4025
Claims Analysis
Total Claims: 39
Claim 1
Independent Claim
159 words
In combination: a laser diode bar having a plurality of emitter regions; a microlens comprising an optical fiber having a linear axis oriented substantially perpendicular to and positioned in the emission path of radiation from said emitter regions to be optically coupled thereto and spaced therefrom by a distance selected to achieve a desired imaging, a first end of said optical fiber mounted in a fixed position with respect to said laser diode bar; slip-fit mounting means for adapted to receive and hold a second end of said optical fiber such that said optical fiber remains substantially on said axis as its length varies due to thermal expansion and contraction; a plurality of optical fibers equal to the number of emitter regions of said laser diode bar, and oriented on axis with respect to said microlens such that radiation from said individual ones of said emitter regions is optically coupled into individual ones of said plurality of optical fibers.
Claim 2
Dependent Claim
159 words
In combination: a laser diode bar having a plurality of emitter regions; a microlens comprising an optical fiber having a linear axis oriented substantially perpendicular to and positioned in the emission path of radiation from said emitter regions to be optically coupled thereto and spaced therefrom by a distance selected to achieve a desired imaging, a first end of said optical fiber mounted in a fixed position with respect to said laser diode bar; slip-fit mounting means for adapted to receive and hold a second end of said optical fiber such that said optical fiber remains substantially on said axis as its length varies due to thermal expansion and contraction; a plurality of optical fibers equal to the number of emitter regions of said laser diode bar, and oriented on axis with respect to said microlens such that radiation from said individual ones of said emitter regions is optically coupled into individual ones of said plurality of optical fibers.
Claim 3
Dependent Claim
34 words
The combination of claim 1 wherein said microlens is substantially cylindrical in cross section and has a diameter chosen to be about 20% to 50% larger than the lateral dimension of said emitter regions.
Claim 4
Dependent Claim
30 words
The combination of claim 2 wherein the diameter of each one of said plurality of optical fibers is chosen to be about equal to the diameter of said cylindrical microlens.
Claim 5
Dependent Claim
13 words
The combination of claim 2 wherein said cylindrical microlens has an anti-reflective coating.
Claim 6
Dependent Claim
63 words
The combination of claim 1 wherein said microlens has a cross sectional shape selected to correct a selected spherical aberration and with an effective aperture approximately the same size as each one of said plurality of optical fibers, said microlens placed at a distance from the output facets of the emitters on the diode bar, said distance selected to achieve a desired imaging.
Claim 7
Dependent Claim
16 words
The combination of claim 5 wherein said distance is approximately one focal length of said microlens.
Claim 8
Dependent Claim
37 words
The combination of claim 1 wherein the numerical aperture of each one of said plurality of optical fibers is chosen to be about equal to the numerical aperture in the low numerical aperture direction said emitter regions.
Claim 9
Dependent Claim
25 words
The combination of claim 7, wherein the numerical aperture of each one of said optical fibers is chosen to be between about 0.1 to 0.2.
Claim 10
Dependent Claim
12 words
The combination of claim 1 wherein said microlens is an optical fiber.
Claim 11
Dependent Claim
20 words
The combination of claim 1, further including a focussing lens at the far end of said plurality of optical fibers.
Claim 12
Dependent Claim
44 words
The combination of claim 1 wherein said slip-fit mounting means comprises a receiving member fixedly mounted with respect to said laser diode bar, said receiving member including a recess therein oriented on said axis, said recess holding said second end of said optical fiber.
Claim 13
Dependent Claim
13 words
The combination of claim 11 wherein said receiving member comprises a precision sleeve.
Claim 14
Dependent Claim
16 words
The combination of claim 1 wherein said distance is approximately one focal length of said microlens.
Claim 15
Dependent Claim
164 words
In combination: a laser diode bar having a plurality of emitter regions; a cylindrical microlens comprising an optical fiber having a linear axis positioned in the emission path of radiation from said emitter regions and spaced therefrom by a distance approximately equal to R(2-n)/2(n-1), where R is the radius of and n is the index of refraction of said microlens, a first end of said optical fiber mounted in a fixed position with respect to said laser diode bar; slip-fit mounting means for adapted to receive and hold a second end of said optical fiber such that said optical fiber remains substantially on said axis as its length varies due to thermal expansion and contraction; a plurality of optical fibers equal to the number of emitter regions of said laser diode bar, and oriented on axis with respect to said microlens such that radiation from said individual ones of said emitter regions is optically coupled into individual ones of said plurality of optical fibers.
Claim 16
Dependent Claim
164 words
In combination: a laser diode bar having a plurality of emitter regions; a cylindrical microlens comprising an optical fiber having a linear axis positioned in the emission path of radiation from said emitter regions and spaced therefrom by a distance approximately equal to R(2-n)/2(n-1), where R is the radius of and n is the index of refraction of said microlens, a first end of said optical fiber mounted in a fixed position with respect to said laser diode bar; slip-fit mounting means for adapted to receive and hold a second end of said optical fiber such that said optical fiber remains substantially on said axis as its length varies due to thermal expansion and contraction; a plurality of optical fibers equal to the number of emitter regions of said laser diode bar, and oriented on axis with respect to said microlens such that radiation from said individual ones of said emitter regions is optically coupled into individual ones of said plurality of optical fibers.
Claim 17
Dependent Claim
34 words
The combination of claim 14 wherein said microlens is substantially cylindrical in cross section and has a diameter chosen to be about 20% to 50% larger than the lateral dimension of said emitter regions.
Claim 18
Dependent Claim
41 words
The combination of claim 14 wherein said microlens has a cross sectional shape selected to correct a selected spherical aberration and has an effective diameter approximately equal to the diameters of each of said plurality of optical fibers to be coupled.
Claim 19
Dependent Claim
30 words
The combination of claim 14 wherein the diameters of each of said optical fibers to be coupled is chosen to be about equal to the diameter of said cylindrical microlens.
Claim 20
Dependent Claim
26 words
The combination of claim 17, wherein the numerical aperture of each of said plurality of optical fibers is chosen to be between about 0.1 to 0.2.
Claim 21
Dependent Claim
33 words
The combination of claim 14 wherein the numerical aperture of said optical fibers is chosen to be about equal to the numerical aperture in the low numerical aperture direction of said emitter regions.
Claim 22
Dependent Claim
41 words
The combination of claim 14 wherein said optical fibers are rectangular in cross section an have a width chosen to be larger than the emitting area of said emitter regions and have a height of between about 30 to 50 microns.
Claim 23
Dependent Claim
12 words
The combination of claim 14 wherein said microlens has an anti-reflective coating.
Claim 24
Dependent Claim
20 words
The combination of claim 14 further including a focussing lens at the far end of said plurality of optical fibers.
Claim 25
Dependent Claim
44 words
The combination of claim 14 wherein said slip-fit mounting means comprises a receiving member fixedly mounted with respect to said laser diode bar, said receiving member including a recess therein oriented on said axis, said recess holding said second end of said optical fiber.
Claim 26
Dependent Claim
13 words
The combination of claim 23 wherein said receiving member comprises a precision sleeve.
Claim 27
Dependent Claim
219 words
A diode pumped laser system, including: cavity forming means, including an active laser medium; a laser diode bar having a plurality of emitter regions; a microlens comprising an optical fiber having a linear axis oriented substantially perpendicular to and positioned in the emission path of radiation from said emitter regions to be optically coupled thereto and spaced therefrom by a distance of approximately one focal length of said microlens, a first end of said optical fiber mounted in a fixed position with respect to said laser diode bar; slip-fit mounting means for adapted to receive and hold a second end of said optical fiber such that said optical fiber remains substantially on said axis as its length varies due to thermal expansion and contraction;; a plurality of optical fibers equal to the number of emitter regions of said laser diode bar, each of said plurality of optical fibers having a first end and a second end, each of said first ends oriented on axis with respect to said microlens such that radiation from said individual ones of said emitter regions is optically coupled into individual ones of said plurality of optical fibers, said second ends of each of said plurality of optical fibers arranged in a bundle; means for optically coupling radiation from said bundle into said laser cavity.
Claim 28
Dependent Claim
219 words
A diode pumped laser system, including: cavity forming means, including an active laser medium; a laser diode bar having a plurality of emitter regions; a microlens comprising an optical fiber having a linear axis oriented substantially perpendicular to and positioned in the emission path of radiation from said emitter regions to be optically coupled thereto and spaced therefrom by a distance of approximately one focal length of said microlens, a first end of said optical fiber mounted in a fixed position with respect to said laser diode bar; slip-fit mounting means for adapted to receive and hold a second end of said optical fiber such that said optical fiber remains substantially on said axis as its length varies due to thermal expansion and contraction;; a plurality of optical fibers equal to the number of emitter regions of said laser diode bar, each of said plurality of optical fibers having a first end and a second end, each of said first ends oriented on axis with respect to said microlens such that radiation from said individual ones of said emitter regions is optically coupled into individual ones of said plurality of optical fibers, said second ends of each of said plurality of optical fibers arranged in a bundle; means for optically coupling radiation from said bundle into said laser cavity.
Claim 29
Dependent Claim
220 words
A diode pumped laser system, including: cavity forming means, including an active laser medium; a laser diode bar having a plurality of emitter regions; a microlens comprising an optical fiber having a linear axis oriented substantially perpendicular to and positioned in the emission path of radiation from said emitter regions to be optically coupled thereto and spaced therefrom by a distance of approximately one focal length of said microlens, a first end of said optical fiber mounted in a fixed position with respect to said laser diode bar; slip-fit mounting means for adapted to receive and hold a second end of said optical fiber such that said optical fiber remains substantially on said axis as its length varies due to thermal expansion and contraction;; a plurality of optical fibers equal to the number of emitter regions of said laser diode bar, each of said plurality of optical fibers having a first end and a second end, each of said first ends oriented on axis with respect to said microlens such that radiation from said individual ones of said emitter regions is optically coupled into individual ones of said plurality of optical fibers, said second ends of each of said optical fibers arranged in a bundle, means for optically coupling radiation from said bundle into one end of said laser cavity.
Claim 30
Dependent Claim
220 words
A diode pumped laser system, including: cavity forming means, including an active laser medium; a laser diode bar having a plurality of emitter regions; a microlens comprising an optical fiber having a linear axis oriented substantially perpendicular to and positioned in the emission path of radiation from said emitter regions to be optically coupled thereto and spaced therefrom by a distance of approximately one focal length of said microlens, a first end of said optical fiber mounted in a fixed position with respect to said laser diode bar; slip-fit mounting means for adapted to receive and hold a second end of said optical fiber such that said optical fiber remains substantially on said axis as its length varies due to thermal expansion and contraction;; a plurality of optical fibers equal to the number of emitter regions of said laser diode bar, each of said plurality of optical fibers having a first end and a second end, each of said first ends oriented on axis with respect to said microlens such that radiation from said individual ones of said emitter regions is optically coupled into individual ones of said plurality of optical fibers, said second ends of each of said optical fibers arranged in a bundle, means for optically coupling radiation from said bundle into one end of said laser cavity.
Claim 31
Dependent Claim
235 words
A diode pumped laser system, including: a bar of active solid state laser material disposed in a laser cavity having opposing ends, one face of said bar forming a first one of said opposing ends; a laser diode bar having a plurality of emitter regions; a microlens comprising an optical fiber having a linear axis oriented substantially perpendicular to and positioned in the emission path of radiation from said emitter regions to be optically coupled thereto and spaced therefrom by a distance selected to achieve a desired imaging, a first end of said optical fiber mounted in a fixed position with respect to said laser diode bar; slip-fit mounting means for adapted to receive and hold a second end of said optical fiber such that said optical fiber remains substantially on said axis as its length varies due to thermal expansion and contraction;; a plurality of optical fibers equal to the number of emitter regions of said laser diode bar each of said optical fibers having a first end and a second end, each of said first ends oriented on axis with respect to said microlens such that radiation from said individual ones of said emitter regions is optically coupled into individual ones of said fibers, said second ends of each of said optical fibers arranged in a bundle; means for optically coupling radiation from said bundle into said first end of said laser cavity.
Claim 32
Dependent Claim
235 words
A diode pumped laser system, including: a bar of active solid state laser material disposed in a laser cavity having opposing ends, one face of said bar forming a first one of said opposing ends; a laser diode bar having a plurality of emitter regions; a microlens comprising an optical fiber having a linear axis oriented substantially perpendicular to and positioned in the emission path of radiation from said emitter regions to be optically coupled thereto and spaced therefrom by a distance selected to achieve a desired imaging, a first end of said optical fiber mounted in a fixed position with respect to said laser diode bar; slip-fit mounting means for adapted to receive and hold a second end of said optical fiber such that said optical fiber remains substantially on said axis as its length varies due to thermal expansion and contraction;; a plurality of optical fibers equal to the number of emitter regions of said laser diode bar each of said optical fibers having a first end and a second end, each of said first ends oriented on axis with respect to said microlens such that radiation from said individual ones of said emitter regions is optically coupled into individual ones of said fibers, said second ends of each of said optical fibers arranged in a bundle; means for optically coupling radiation from said bundle into said first end of said laser cavity.
Claim 33
Independent Claim
194 words
A method of coupling the output of a laser diode emitter region into the end of an optical fiber including the steps of: mounting along a linear axis spaced from said laser diode a microlens comprising an optical fiber, said microlens spaced from said laser diode by about R(2-n)/2(n-1), where R is the radius of and n is the index of refraction of said microlens, said microlens having a diameter about 20% to 50% larger than the lateral dimension of said emitter region, said microlens mounted such that a first one of its ends is in a fixed position and a second one of its ends is slidable along said linear axis; optically coupling the output radiation of said laser diode emitter region into said microlens; optically coupling the output radiation of said microlens into the end of an optical fiber, said optical fiber having a diameter about equal to the diameter of said microlens, said end of said optical fiber spaced as close as possible to said microlens, said optical fiber having a numerical aperture about equal to the numerical aperture of said emitter region of said laser diode in its low direction.
Claim 34
Independent Claim
194 words
A method of coupling the output of a laser diode emitter region into the end of an optical fiber including the steps of: mounting along a linear axis spaced from said laser diode a microlens comprising an optical fiber, said microlens spaced from said laser diode by about R(2-n)/2(n-1), where R is the radius of and n is the index of refraction of said microlens, said microlens having a diameter about 20% to 50% larger than the lateral dimension of said emitter region, said microlens mounted such that a first one of its ends is in a fixed position and a second one of its ends is slidable along said linear axis; optically coupling the output radiation of said laser diode emitter region into said microlens; optically coupling the output radiation of said microlens into the end of an optical fiber, said optical fiber having a diameter about equal to the diameter of said microlens, said end of said optical fiber spaced as close as possible to said microlens, said optical fiber having a numerical aperture about equal to the numerical aperture of said emitter region of said laser diode in its low direction.
Claim 35
Dependent Claim
33 words
The method of claim 28 including the further step of optically coupling a focussing lens to the far end of a plurality of said optical fibers arranged as a bundle of optical fibers.
Claim 36
Independent Claim
219 words
A method of coupling the output of the emitter regions of a plurality of laser diodes into a fiber optic bundle including the steps of: mounting along a linear axis spaced form said laser diode a microlens comprising an optical fiber, said microlens spaced from said emitter regions by about R(2-n)/2(n-1), where R is the radius of and n is the index of refraction of said microlens, said microlens having a diameter about 20% to 50% larger than the lateral dimension of said emitter region, said microlens mounted such that a first one of its ends is in a fixed position and a second one of its ends is slidable along said linear axis; optically coupling the output radiation of said each of said emitter regions into a different region of said microlens; separately optically coupling the output radiation of said microlens corresponding to the output of each of said emitter regions into the ends of different ones of a plurality of optical fibers, each of said optical fibers having a diameter about equal to the diameter of said microlens, the ends of said optical fibers spaced as closely as possible to said microlens, said optical fibers having a numerical aperture about equal to the numerical aperture of said emitter regions of said laser diode in its low direction.
Claim 37
Independent Claim
219 words
A method of coupling the output of the emitter regions of a plurality of laser diodes into a fiber optic bundle including the steps of: mounting along a linear axis spaced form said laser diode a microlens comprising an optical fiber, said microlens spaced from said emitter regions by about R(2-n)/2(n-1), where R is the radius of and n is the index of refraction of said microlens, said microlens having a diameter about 20% to 50% larger than the lateral dimension of said emitter region, said microlens mounted such that a first one of its ends is in a fixed position and a second one of its ends is slidable along said linear axis; optically coupling the output radiation of said each of said emitter regions into a different region of said microlens; separately optically coupling the output radiation of said microlens corresponding to the output of each of said emitter regions into the ends of different ones of a plurality of optical fibers, each of said optical fibers having a diameter about equal to the diameter of said microlens, the ends of said optical fibers spaced as closely as possible to said microlens, said optical fibers having a numerical aperture about equal to the numerical aperture of said emitter regions of said laser diode in its low direction.
Claim 38
Independent Claim
125 words
A method for mounting a microlens comprising an optical fiber for collimating the output radiation from at least one laser diode emitter, comprising the steps of: providing a fixed mount for a first end of said optical fiber in a position along a linear axis perpendicular to the axis of emission from said at least one laser diode emitter, said linear axis spaced from the face of said at least one laser diode emitter by a distance selected to achieve maximum collimation of said emission; and providing a slidable mount for a second end of said optical fiber along said linear axis perpendicular to said axis of emission such that said optical fiber may slide with respect to said slidable mount along said linear axis.
Claim 39
Independent Claim
125 words
A method for mounting a microlens comprising an optical fiber for collimating the output radiation from at least one laser diode emitter, comprising the steps of: providing a fixed mount for a first end of said optical fiber in a position along a linear axis perpendicular to the axis of emission from said at least one laser diode emitter, said linear axis spaced from the face of said at least one laser diode emitter by a distance selected to achieve maximum collimation of said emission; and providing a slidable mount for a second end of said optical fiber along said linear axis perpendicular to said axis of emission such that said optical fiber may slide with respect to said slidable mount along said linear axis.
References Cited (Backward Citations)
US5127068A
Cited
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