EP0571126A2
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EP
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Apparatus and method for optical energy amplification using two-beam coupling
Assignee: The AT&T MVPD Group LLC
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Filing: 1993-05-12
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Granted: —
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Expires: 2013-05-12
Abstract
Abstract A diffraction limited working beam (14) at a given frequency is amplified without degrading its diffraction limited quality by diverting a minor portion of the beam as a probe beam, and amplifying the remaining portion of the working beam (14) with a high power pump beam (12) at a different wavelength. The amplification takes place in a host medium (10, 28) that has a rare earth dopant with an energy transition from the pump beam's wavelength to the wavelength of the working beam. The resulting amplified working beam is non-diffraction limited. The probe beam is frequency modulated and coupled with the amplified working beam in a second host medium (22) that also has a rare earth dopant. Energy is transferred from the amplified working beam to the modulated probe beam through a resonant energy transfer in the second host medium (22), producing an amplified output beam at the working beam frequency that retains the diffraction limited quality of the probe beam.
Inventors
- 👤 Juan F. Lam
- 👤 Huan-Wun Yen
- 👤 Joseph L. Pikulski
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-08 16:11
CPC Classifications
G; G02; G02F; G02F1/00; G02F1/35; G02F1/39; G02F1/397; G02B; G02B6/00; G02B6/04; G02B6/24; G02B6/26; G02B6/28; G02B6/2804; G02B6/2856; G02B6/42; G02B6/4201; G02B6/4204; G02B6/4206; H; H01; H01S; H01S3/00; H01S3/23; H01S3/2383; H01S3/005; H01S3/05; H01S3/06; H01S3/063; H01S3/067; H01S3/06754; H01S3/06783
Claims Analysis
Total Claims: 22
Claim 1
Independent Claim
175 words
An optical energy transfer system, comprising: means (4, 2) for producing a working optical beam (14) and a pump optical beam (12) having different respective wavelengths, means (8) for diverting a portion of said working beam (14) to establish a probe beam, means (18) for modulating the frequency of said probe beam, a first host medium (10, 28) having a rare earth dopant with an energy transition from said pump beam's (12) wavelength to the wavelength of said working beam (14), first coupling means (6) for coupling said pump beam (12) and the undiverted portion of said working beam (14) into said first host medium (10, 28) for amplification of said working beam (14) by an energy transfer from said pump beam (12), a second host medium (22) having a rare earth dopant, and second coupling means (20, 24) for coupling said amplified working beam (14) and said modulated probe beam into said second host medium (22) for amplification of said modulated probe beam by a resonant energy transfer from said amplified working beam (14).
Claim 2
Dependent Claim
37 words
The optical energy transfer system of claim 1, wherein said modulated probe beam is substantially diffraction limited and said amplified working beam (14) is substantially non-diffraction limited when they are coupled into said second host medium (22).
Claim 3
Dependent Claim
31 words
The optical energy transfer system of claim 1, wherein said beam producing means (2, 4) produces said pump beam (12) at a substantially higher power level than said working beam (14).
Claim 4
Dependent Claim
37 words
The optical energy transfer system of claim 3, wherein the wavelengths of said working and pump beams (14, 12) are respectively about 1.55 and 0.98 microns, and said first host medium (10, 28) is doped with erbium.
Claim 5
Dependent Claim
42 words
The optical energy transfer system of claim 1, said modulating means (18) comprising means for frequency modulating said probe beam to establish a resonant energy transfer interference pattern between said modulated probe and amplified working beams within said second host medium (22).
Claim 6
Dependent Claim
16 words
The optical energy transfer system of claim 5, said modulating means (18) comprising an acousto-optic modulator.
Claim 7
Dependent Claim
48 words
The optical energy transfer system of claim 1, said first host medium comprising a plurality of optical fibers (10) disposed to receive an input from said first coupling means (6) at one end and to provide an output to said second coupling means (20) at their opposite ends.
Claim 8
Dependent Claim
80 words
The optical energy transfer system of claim 7, wherein the input ends of said optical fibers (10) are arranged in an m x m array, and said first coupling means comprises a pair of 1 x m mutually orthogonal binary phase gratings (44, 46, 38, 40) oriented to divide said working and pump beams into an m x m array aligned with the input ends of said optical fibers (10), and means (8) for combining said working and pump beams.
Claim 9
Dependent Claim
30 words
The optical energy transfer system of claim 7, said fibers (10) having cladded cores, wherein the areas of said cores are expanded at the input ends (58) of said fibers.
Claim 10
Dependent Claim
52 words
The optical energy transfer system of claim 7, said fibers comprising cores surrounded by cladding layers, wherein the thickness of said cladding layers is reduced at the output ends (80) of said fibers, and further comprising means (50) holding the output ends (80) of said fibers in close proximity to each other.
Claim 11
Dependent Claim
30 words
The optical energy transfer system of claim 7, wherein said fibers are joined to each other at their input ends, and separated in a spaced array at their output ends.
Claim 12
Dependent Claim
101 words
The optical energy transfer system of claim 11, wherein the areas of said fibers are reduced at their input ends, and said first coupling means includes a coupling optical fiber (56) that is single mode with respect to said working beam (14), said coupling fiber (56) having an input end (58) that is enlarged with respect to the input ends of said host medium fibers and an output end (60) positioned to illuminate the input ends of said host medium fibers, and means (54) for focusing said working and pump beams onto the input end (58) of said coupling fiber (56).
Claim 13
Dependent Claim
97 words
The optical energy transfer system of claim 11, wherein the areas of said fibers (10) are reduced at their input ends and said first coupling means includes a plurality of single-mode optical coupling fibers (84, 86) having output ends positioned to illuminate said host medium fibers (10) and input ends, and means (8, 82) for focusing said working beam (14) onto the input end of at least one of said coupling fibers (86) and said pump beam (12) onto the input ends of a greater number of coupling fibers (84) than those that receive said working beam.
Claim 14
Dependent Claim
17 words
The optical energy transfer system of claim 1 said first host medium comprising an optical waveguide (28).
Claim 15
Dependent Claim
131 words
An optical energy transfer system, comprising: first and second sources (4, 2) of working and pump optical beams (14, 12) at different respective wavelengths, means (8) for diverting a portion of said working beam (14) into a probe beam, means (18) for modulating the frequency of said probe beam, means (10, 28) for transferring energy from said pump beam (12) to said working beam (14) after diversion of said probe beam, thereby amplifying said working beam (14), a rare earth doped resonant transfer host medium (22), and means for coupling said frequency modulated probe beam and amplified working beam (14) within said resonant transfer host medium (22) to beat against each other and generate gratings that effect a resonant energy transfer from said amplified working beam (14) to said probe beam.
Claim 16
Dependent Claim
65 words
The optical energy transfer system of claim 15, wherein said working beam source (4) generates said working beam (14) and probe beam as substantially diffraction limited beams, said energy transfer means (10, 28) causes said amplified working beam (14) to be substantially non-diffraction-limited, and said resonant transfer host medium (22) substantially preserves the diffraction limited quality of said probe beam during said energy transfer thereto.
Claim 17
Dependent Claim
61 words
The optical energy transfer system of claim 15, said energy transfer means (10, 28) comprising a first host medium having a rare earth dopant with an energy transition from the wavelength of said pump beam (12) to the wavelength of said working beam (14), and means (6) for coupling said working and pump beams (14, 12) into said first host medium.
Claim 18
Dependent Claim
62 words
An optical fiber array, comprising: a plurality of elongate optical fibers (10) having respective optical cores (78) surrounded by cladding layers (76), the thickness of the cladding layer for each of the fibers being reduced in the vicinity of one end (80) of the fibers, and means (50) holding said reduced thickness ends of the fibers in close proximity to each other.
Claim 19
Dependent Claim
30 words
The optical fiber array of claim 18, wherein the opposite ends (76) of said fibers from said reduced thickness ends (80) are joined together in a common optical fiber (68).
Claim 20
Dependent Claim
114 words
A diffraction limited method of transferring energy from an optical pump beam (12) at one wavelength to an optical working beam (14) at another wavelength, comprising: generating said working beam (14) as a substantially diffraction limited beam, diverting a portion of said working beam (14) as a substantially diffraction limited probe beam, transferring energy from said pump beam (12) to said working (14) beam after diversion of said probe beam to yield a substantially non-diffraction limited amplified working beam, and transferring energy from said amplified working beam (14) to said probe beam in a substantially diffraction-limited energy transfer process to yield a substantially diffraction limited amplified probe beam (26) at said working beam wavelength.
Claim 21
Dependent Claim
54 words
The method of claim 20, wherein energy is transferred from said pump beam (12) to said working beam (14) by transmitting said beams through a host medium (10, 28) having a rare earth dopant with an energy transition from the wavelength of said pump beam (12) to the wavelength of said working beam (14).
Claim 22
Dependent Claim
71 words
The method of claim 20, wherein energy is transferred from said amplified working beam (14) to said probe beam by frequency modulating said probe beam, and beating said frequency modulated probe beam against said amplified working beam in a host medium (22) having a rare earth dopant to generate optical gratings in said medium (22) that scatter said amplified working beam (14) to effect a resonant energy transfer between said beams.
References Cited (Backward Citations)
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