US5208881A
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US
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Method and apparatus for optical beam combination and cleanup using stimulated scattering
Assignee: The AT&T MVPD Group LLC
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Filing: 1991-12-20
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Granted: 1993-05-04
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Expires: 2011-12-20
Abstract
Abstract An optical beam is made closer to diffraction limited by coupling it into a multi-mode guide, such as an optical fiber, of sufficient length to generate a stimulated Brillouin scattering (SBS) return beam with improved divergence. For this purpose the term ΔkL is made substantially greater than π, where Δk is the difference in propagation vectors between the input and SBS beams, and L is the mutual interaction length of the input and SBS beams within the fiber. Beam amplification can also be provided by coupling a plurality of low power input beams that have respective wavelengths within the fiber's SBS linewidth into the fiber so that each of the input beams transfers energy into the SBS beam, which emerges with a power greater than that of any of its inputs. The beam cleanup and amplification functions are capable of operating with continuous wave or pulsed inputs.
Inventors
- 👤 Hans W. Bruesselbach
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 21:05
CPC Classifications
H; H01; H01S; H01S3/00; H01S3/30; H01S3/302; H01S3/005
Claims Analysis
Total Claims: 29
Claim 1
Independent Claim
124 words
An optical beam processing system for producing a diffraction limited output beam, comprising: a beam source for providing a divergent input optical beam, an elongate beam guiding means, and means for coupling said input optical beam from said beam source into said beam guiding means, said beam guiding means having a normalized frequency value large enough to support substantially multi-mode propagation of said input optical beam, and a length which is long enough to generate a diffraction limited return beam which is substantially more diffraction limited than said input optical beam through stimulated scattering in response to said input optical beam being coupled into said beam guiding means, said diffraction limited return beam exiting said beam guiding means as said diffraction limited output beam.
Claim 2
Dependent Claim
124 words
An optical beam processing system for producing a diffraction limited output beam, comprising: a beam source for providing a divergent input optical beam, an elongate beam guiding means, and means for coupling said input optical beam from said beam source into said beam guiding means, said beam guiding means having a normalized frequency value large enough to support substantially multi-mode propagation of said input optical beam, and a length which is long enough to generate a diffraction limited return beam which is substantially more diffraction limited than said input optical beam through stimulated scattering in response to said input optical beam being coupled into said beam guiding means, said diffraction limited return beam exiting said beam guiding means as said diffraction limited output beam.
Claim 3
Dependent Claim
14 words
The system of claim 1, wherein said stimulated scattering comprises stimulated Brillouin scattering (SBS).
Claim 4
Dependent Claim
48 words
The system of claim 1, said beam source providing a plurality of input optical beams, said coupling means coupling each of said input beams into said beam guiding means, said beam guiding means combining a substantial portion of the powers of said input beams into said return beam.
Claim 5
Dependent Claim
28 words
The system of claim 3, wherein said input beams are substantially non-diffraction limited, and said return beam is substantially more diffraction limited than any of said input beams.
Claim 6
Dependent Claim
49 words
The system of claim 1, wherein ΔkL is substantially greater than π, where Δk is the difference in propagation vectors between said input beam and said return beam in said beam guiding means, and L is the mutual interaction length of said input beams within said beam guiding means.
Claim 7
Dependent Claim
12 words
The system of claim 5, wherein ΔkL is greater than about 10π.
Claim 8
Dependent Claim
43 words
The system of claim 1, said beam guiding means comprising an optical fiber having a core surrounded by a cladding layer, said core and cladding layer being selected to have a refractive index differential that substantially restricts said input beam to said core.
Claim 9
Dependent Claim
19 words
The system of claim 7, said optical fiber having a graded transition between said core and said cladding layer.
Claim 10
Dependent Claim
19 words
The system of claim 7, said optical fiber having an abrupt transition between said core and said cladding layer.
Claim 11
Dependent Claim
27 words
The system of claim 1, wherein said input beam is substantially non-diffraction limited, and said return beam is substantially closer to diffraction limited than said input beam.
Claim 12
Dependent Claim
19 words
The system of claim 1, wherein said beam source provides said input optical beam as a continuous wave beam.
Claim 13
Dependent Claim
18 words
The system of claim 1, said beam guiding means comprising a capillary filled with a liquid SBS medium.
Claim 14
Dependent Claim
160 words
An optical beam processing system for producing a diffraction limited output beam, comprising: a beam source for providing a divergent input optical beam, an elongate beam guiding means, and means for coupling said input optical beam from said beam source into said beam guiding means, said beam guiding means having guiding parameters capable of supporting substantially multi-mode propagation of said input optical beam, and a length which is long enough to generate a diffraction limited return beam which is substantially more diffraction limited than said input optical beam through stimulated scattering in response to said input optical beam being coupled into said beam guiding means, wherein said stimulated scattering comprises stimulated Brillouin scattering (SBS), and wherein said input optical beams are individually low power beams below the SBS threshold of said guiding means but have an aggregate power greater than said SBS threshold, and said input optical beams have respective wavelengths within the SBS linewidth of said beam guiding means.
Claim 15
Dependent Claim
160 words
An optical beam processing system for producing a diffraction limited output beam, comprising: a beam source for providing a divergent input optical beam, an elongate beam guiding means, and means for coupling said input optical beam from said beam source into said beam guiding means, said beam guiding means having guiding parameters capable of supporting substantially multi-mode propagation of said input optical beam, and a length which is long enough to generate a diffraction limited return beam which is substantially more diffraction limited than said input optical beam through stimulated scattering in response to said input optical beam being coupled into said beam guiding means, wherein said stimulated scattering comprises stimulated Brillouin scattering (SBS), and wherein said input optical beams are individually low power beams below the SBS threshold of said guiding means but have an aggregate power greater than said SBS threshold, and said input optical beams have respective wavelengths within the SBS linewidth of said beam guiding means.
Claim 16
Independent Claim
59 words
A method of producing a diffraction limited output beam in response to a non-diffraction limited source optical beam, comprising: directing said source beam in a multi-mode propagation through an optical guide for a sufficient distance to generate a return beam within said optical guide through stimulated scattering, and coupling out said return beam as said diffraction limited output beam.
Claim 17
Independent Claim
59 words
A method of producing a diffraction limited output beam in response to a non-diffraction limited source optical beam, comprising: directing said source beam in a multi-mode propagation through an optical guide for a sufficient distance to generate a return beam within said optical guide through stimulated scattering, and coupling out said return beam as said diffraction limited output beam.
Claim 18
Dependent Claim
16 words
The method of claim 14, wherein said return beam is generated through stimulated Brillouin scattering (SBS).
Claim 19
Dependent Claim
14 words
The method of claim 14, wherein said source beam is a continuous wave beam.
Claim 20
Dependent Claim
26 words
The method of claim 14, wherein said source beam is propagated through an optical guide that comprises an optical fiber core surrounded by a cladding material.
Claim 21
Independent Claim
77 words
A method of combining a plurality of input optical beams into an output beam, comprising: directing said input optical beams together in a multi-mode propagation through a beam guiding medium at least long enough to generate a return stimulated scattering beam within said beam guiding medium, energy being transferred from said input optical beams to said return stimulated scattering beam through a stimulated scattering process, and coupling out said return stimulated scattering beam as said output beam.
Claim 22
Independent Claim
77 words
A method of combining a plurality of input optical beams into an output beam, comprising: directing said input optical beams together in a multi-mode propagation through a beam guiding medium at least long enough to generate a return stimulated scattering beam within said beam guiding medium, energy being transferred from said input optical beams to said return stimulated scattering beam through a stimulated scattering process, and coupling out said return stimulated scattering beam as said output beam.
Claim 23
Dependent Claim
16 words
The method of claim 18, wherein said return beam is generated through stimulated Brillouin scattering (SBS).
Claim 24
Dependent Claim
48 words
The method of claim 19, wherein said input beams are individually low power beams below the SBS threshold of said beam guiding medium but have an aggregate power greater than said SBS threshold, said input beams having respective wavelengths within the SBS linewidth of said beam guiding medium.
Claim 25
Dependent Claim
28 words
The method of claim 18, wherein said input beams are substantially non-diffraction limited, and said return beam is substantially more diffraction limited than any of said input beams.
Claim 26
Dependent Claim
49 words
The method of claim 18, wherein ΔkL is substantially greater than π, where Δk is the difference in propagation vectors between said input beams and said return beam in said beam guiding medium, and L is the mutual interaction length of said input beams within said beam guiding means.
Claim 27
Dependent Claim
12 words
The method of claim 22, wherein ΔkL is greater than about 10π.
Claim 28
Dependent Claim
13 words
The method of claim 18, wherein said input beams are continuous wave beams.
Claim 29
Dependent Claim
27 words
The method of claim 18, wherein said input beams are propagated through a beam guiding medium that comprises an optical fiber core surrounded by a cladding material.
References Cited (Backward Citations)
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