US4642582A
Expired / Lapsed
US
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Nonlinear delay line encoding/decoding arrangements
Assignee: The AT&T MVPD Group LLC
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Filing: 1986-02-26
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Granted: 1987-02-10
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Expires: 2006-02-26
Abstract
Abstract Apparatus for encoding and decoding laser pulses, or the like. At least one laser source applied laser energy to a nonlinear material in a manner such that counter-propagating beams are applied to the material. These laser beams are spatially or temporally modulated in a predetermined manner. The modulation may be continuous, or discrete, amplitude or phase modulation. Another laser source provides a probe pulse which traverses the nonlinear material and interacts with the counter-propagating laser beams in a manner known as four-wave mixing. This process generates an encoded laser pulse whose modulation pattern is a function of the modulation of the counter-propagating beams. A decoded laser pulse is obtained by applying the encoded pulse to the apparatus and reversing the modulation of the counter-propagating laser beams.
Inventors
- 👤 Thomas R. O'Meara
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 10:49
CPC Classifications
G; G02; G02F; G02F1/00; G02F1/35; G02F1/353; G02F1/3534
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
148 words
An encoding system for encoding and coherently modulating laser pulses, said system comprising: a nonlinear medium having a predetermined length and cross-section and being capable of undergoing four-wave mixing; first laser means for applying laser pulses to said nonlinear medium such that said pulses traverse the length thereof; second laser means for applying light such that said light impinges upon said medium from two predetermined directions to provide pump beams for said four-wave mixing; and means for phase-encoding said light from said second laser means such that it has a predetermined spatial modulation thus providing spatially modulated laser light; whereby said applied laser pulses traverse the length of said medium and interact with said spatially modulated laser light in a manner which produces said four-wave mixing in said medium, said four-wave mixing generating elongated encoded laser pulses which are temporally modulated in accordance with said predetermined spatial modulation.
Claim 2
Dependent Claim
148 words
An encoding system for encoding and coherently modulating laser pulses, said system comprising: a nonlinear medium having a predetermined length and cross-section and being capable of undergoing four-wave mixing; first laser means for applying laser pulses to said nonlinear medium such that said pulses traverse the length thereof; second laser means for applying light such that said light impinges upon said medium from two predetermined directions to provide pump beams for said four-wave mixing; and means for phase-encoding said light from said second laser means such that it has a predetermined spatial modulation thus providing spatially modulated laser light; whereby said applied laser pulses traverse the length of said medium and interact with said spatially modulated laser light in a manner which produces said four-wave mixing in said medium, said four-wave mixing generating elongated encoded laser pulses which are temporally modulated in accordance with said predetermined spatial modulation.
Claim 3
Dependent Claim
178 words
A decoding system for decoding an applied laser pulse temporally modulated in accordance with a predetermined spatial modulation, said arrangement comprising: a nonlinear medium having a predetermined length and cross-section and being capable of undergoing four-wave mixing; means for applying said encoded pulse to said nonlinear medium such that said pulse traverses the length thereof; laser means for applying laser light across said nonlinear medium such that said light impinges upon said medium from two predetermined directions to provide pump beams for said four-wave mixing; means for modulating said laser light such that it has a spatial modulation which is spatially-reversed with respect to said predetermined spatial modulation employed to encode said applied laser pulse; and whereby said applied laser pulse traverses the length of said medium and intereacts with said spatially modulated laser light in a manner which produces said four-wave mixing in said medium, said four-wave mixing generating a decoded laser pulse which is the convolution of said predetermined spatial modulation of said modulated laser light and said encoded temporal modulation of said applied laser pulse.
Claim 4
Dependent Claim
178 words
A decoding system for decoding an applied laser pulse temporally modulated in accordance with a predetermined spatial modulation, said arrangement comprising: a nonlinear medium having a predetermined length and cross-section and being capable of undergoing four-wave mixing; means for applying said encoded pulse to said nonlinear medium such that said pulse traverses the length thereof; laser means for applying laser light across said nonlinear medium such that said light impinges upon said medium from two predetermined directions to provide pump beams for said four-wave mixing; means for modulating said laser light such that it has a spatial modulation which is spatially-reversed with respect to said predetermined spatial modulation employed to encode said applied laser pulse; and whereby said applied laser pulse traverses the length of said medium and intereacts with said spatially modulated laser light in a manner which produces said four-wave mixing in said medium, said four-wave mixing generating a decoded laser pulse which is the convolution of said predetermined spatial modulation of said modulated laser light and said encoded temporal modulation of said applied laser pulse.
Claim 5
Dependent Claim
51 words
The system of claim 2, wherein said means for modulating said laser light comprises: an optical element having an optical coating deposited thereon which has a predetermined spatial pattern, and an optical reflector, disposed on opposite sides of said nonlinear medium for modulating said laser light applied to said nonlinear medium.
Claim 6
Dependent Claim
32 words
The system of claim 2 wherein said means for modulating said laser light comprises: an electro-optic device and electronic control means therefor for modulating said laser light applied to said nonlinear medium.
Claim 7
Dependent Claim
55 words
The system of claim 1 wherein said means for phase-encoding said light from said second laser means comprises: an optical element having an optical coating deposited thereon which has a predetermined spatial pattern, and an optical reflector, disposed on opposite sides of said nonlinear medium for modulating said laser light applied to said nonlinear medium.
Claim 8
Dependent Claim
36 words
The system of claim 1 wherein said means for phase-encoding said light from said second laser means comprises: an electro-optic device and electronic control means therefor for modulating said laser light applied to said nonlinear medium.
Claim 9
Dependent Claim
41 words
The system of claim 2 wherein said laser means comprises: a plurality of laser sources providing light at substantially the same frequency; and a plurality of modulators individually coupled to said pluraltiy of laser sources for modulating laser light provided thereby.
Claim 10
Dependent Claim
42 words
The system of claim 1 wherein said second laser means comprises: a plurality of laser sources providing light at substantially the same frequency; and a plurality of modulators individually coupled to said plurality of laser sources for modulating laser light provided thereby.
References Cited (Backward Citations)
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