Tunable nonlinearly chirped grating
First Claim
Patent Images
1. An optical device, comprising:
- a wave-guiding element having an optic axis to transport optical energy and an effective index of refraction along said optic axis; and
an optical perturbation region formed in said wave-guiding element and configured to have a period along said optic axis,wherein a product of said period and said effective index of refraction is a nonlinear function of a position along said optic axis to effect a phase-matching condition such that a reflected optical wave from said optical perturbation region has a specified wavelength having a nonlinear dependence on a position along said optic axis.
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Abstract
A nonlinearly chirped fiber grating for achieving tunable dispersion compensation, chirp reduction in directly modulated diode lasers, and optical pulse manipulation. A dynamical dispersion compensation mechanism can be implemented in a fiber communication system based on such a nonlinearly chirped fiber grating.
169 Citations
52 Claims
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1. An optical device, comprising:
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a wave-guiding element having an optic axis to transport optical energy and an effective index of refraction along said optic axis; and an optical perturbation region formed in said wave-guiding element and configured to have a period along said optic axis, wherein a product of said period and said effective index of refraction is a nonlinear function of a position along said optic axis to effect a phase-matching condition such that a reflected optical wave from said optical perturbation region has a specified wavelength having a nonlinear dependence on a position along said optic axis. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15)
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16. An optical device, comprising:
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a segment of fiber; a fiber grating formed in said fiber, said fiber grating having a grating period that changes along said fiber in a nonlinear manner to effect different delays for optical waves of different frequencies that are Bragg phase-matched in said fiber grating; and a fiber stretcher engaged to said fiber grating and configured to change a length of said fiber grating to produce a change in relative delays of said optical waves at said different frequencies. - View Dependent Claims (17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28)
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29. An optical system capable of dynamically adjusting dispersion compensation, comprising:
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a dispersion analyzer, operating to receive a portion of an optical signal and determine information about dispersion in said optical signal; and a dispersion compensating element coupled to receive said information from said dispersion analyzer and configured to receive at least a portion of said optical signal and to produce a reflected signal with a reduced amount of dispersion in response to a control signal from said dispersion analyzer, said dispersion compensating element including; a wave-guiding element having an optic axis to transport optical energy and an effective index of refraction which is a function of a position along said optic axis; and a grating formed in said wave-guiding element and configured to have a variable grating period along said optic axis, wherein a product of said variable grating period and said effective index of refraction is a nonlinear function of a position along said optic axis to effect a Bragg phase-matching condition so that a reflected optical wave from said grating has a specified wavelength that has a nonlinear dependence on a position along said optic axis. - View Dependent Claims (30, 31, 32, 33)
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34. An optical device, comprising:
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a semiconductor laser; an electrical power supply connected to said semiconductor laser to provide a modulated driving current which causes a modulated laser output from said laser; a waveguide grating disposed to receive said modulated laser output and having a variable grating period and an effective index of refraction to effect a Bragg phase-matching condition so that a reflected laser beam of said modulated laser output from said waveguide grating has a specified wavelength that has a nonlinear dependence on a position along said waveguide grating; a grating control unit coupled to said power supply and configured to control a dispersion characteristics of said waveguide grating to reduce a frequency chirp in said modulated laser output. - View Dependent Claims (35)
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36. An optical device, comprising:
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a segment of waveguide having an optic axis to transport optical energy; an optical perturbation region formed in said waveguide and having a variation in a refractive index along said optic axis to define a nonlinearly chirped grating, said nonlinearly chirped grating having a position-varying period that changes nonlinearly along said optic axis and reflecting an optical wave of a specified wavelength which has a nonlinear dependence on a position along said optic axis; and a waveguide controller to control a parameter of said optical perturbation region as to vary relative time delays of different spectral components of a reflected optical wave. - View Dependent Claims (37, 38, 39, 40, 41)
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42. A method for operating a fiber system, comprising:
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directing an optical signal that is transmitted through a dispersive signal path into a tunable nonlinearly chirped fiber grating; determining a polarity and an amount of dispersion in said optical signal; and adjusting said tunable nonlinearly chirped fiber grating according to said polarity and amount of dispersion to reduce dispersion in said optical signal. - View Dependent Claims (43, 44, 45, 46, 47, 48, 49, 50, 51, 52)
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Specification