Polarization Mode Emulators and Polarization Mode Dispersion Compensators Based on Optical Polarization Rotators with Discrete Polarization States
First Claim
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1. An optical device, comprising:
- a plurality of differential group delay (DGD) segments each exhibiting optical birefringence to effectuate a DGD between light of two orthogonal polarizations that transmits through each DGD segment, the DGG segments arranged along an optical path and separated from each other along the optical path;
a plurality of tunable optical polarization rotators respectively located in gaps between the DGD segments, one tunable optical polarization rotator per gap to rotate polarization of light after exiting one DGD segment and before entering a downstream DGD segment, each tunable optical polarization rotator responsive to a control signal to produce three different polarization rotations; and
a control module in communication with the tunable optical polarization rotators to individually control each of the optical polarization rotators to produce one of the three different polarization rotations to produce polarization mode dispersion of a first order and one or more higher orders on the light that transmits through the DGD segments and the tunable optical polarization rotators.
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Abstract
Systems, devices and techniques for generating and analyzing states of polarization in light using multiple adjustable polarization rotators having different discrete polarization rotation states in various applications.
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Citations
45 Claims
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1. An optical device, comprising:
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a plurality of differential group delay (DGD) segments each exhibiting optical birefringence to effectuate a DGD between light of two orthogonal polarizations that transmits through each DGD segment, the DGG segments arranged along an optical path and separated from each other along the optical path; a plurality of tunable optical polarization rotators respectively located in gaps between the DGD segments, one tunable optical polarization rotator per gap to rotate polarization of light after exiting one DGD segment and before entering a downstream DGD segment, each tunable optical polarization rotator responsive to a control signal to produce three different polarization rotations; and a control module in communication with the tunable optical polarization rotators to individually control each of the optical polarization rotators to produce one of the three different polarization rotations to produce polarization mode dispersion of a first order and one or more higher orders on the light that transmits through the DGD segments and the tunable optical polarization rotators. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14)
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15. A communication device for optical wavelength division multiplexing (WDM), comprising:
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a WDM demultiplexer that separates optical WDM signals at different WDM wavelengths along different signal paths; and a plurality of optical receivers located in the different signal paths, respectively, each optical receiver receiving one optical WDM signal at a respective WDM wavelength to extract data carried by the received optical WDM signal, wherein each optical receiver includes a polarization mode dispersion (PMD) compensator that includes; a plurality of differential group delay (DGD) segments each exhibiting optical birefringence to effectuate a DGD between light of two orthogonal polarizations that transmits through each DGD segment, the DGG segments arranged along an optical path and separated from each other along the optical path; a plurality of tunable optical polarization rotators respectively located in gaps between the DGD segments, one tunable optical polarization rotator per gap to rotate polarization of light after exiting one DGD segment and before entering a downstream DGD segment, each tunable optical polarization rotator responsive to a control signal to produce three different polarization rotations; and a control module in communication with the tunable optical polarization rotators to individually control each of the optical polarization rotators to produce one of the three different polarization rotations to produce polarization mode dispersion of a first order and one or more higher orders on the light that transmits through the DGD segments and the tunable optical polarization rotators to negate PMD in the received optical WDM signal. - View Dependent Claims (16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30)
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31. An optical device, comprising:
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an input port to receive input light; a plurality of differential group delay (DGD) segments each exhibiting optical birefringence to effectuate a DGD between light of two orthogonal polarizations pass through the DGD segment, the DGG segments arranged separated from one another along an optical path that receives the input light from the input port; a plurality of tunable optical polarization rotators respectively located in gaps between the DGD segments, each tunable optical polarization rotator operable rotates polarization of light after exiting one DGD segment and before entering a downstream DGD segment, the tunable optical polarization rotators including at least one continuously tunable optical rotator responsive to a continuous tuning control signal to continuously rotate polarization of light to reach a desired rotation of the polarization of light, and discrete-state tunable optical polarization rotators responsive to respective discrete-state control signals to produce two or more different discrete polarization rotations; and a control module in communication with the tunable optical polarization rotators to individually control each of the optical polarization rotators, the control module operable to produce varying values of the continuous tuning control signal in operating the continuously tunable optical rotator, and to produce one of discrete values of each discrete-state control signal to operate each respective discrete-state tunable optical polarization rotator to produce a respective one of the two or more discrete polarization rotations. - View Dependent Claims (32, 33, 34, 35, 36, 37)
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38. A method for measuring optical polarization mode dispersion (PMD) in a fiber link, comprising:
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using a WDM demultiplexer to receive optical wavelength-division-multiplexed (WDM) signals at different WDM wavelengths from a fiber link and to separate the received optical WDM signals along different signal paths; using an optical receiver located in one of the different signal paths to receive and process a respective optical WDM signal at a respective WDM wavelength to measure PMD of the optical WDM signal by using differential group delay (DGD) segments separated from each other along the optical path and each exhibiting optical birefringence to effectuate a DGD between light of two orthogonal polarizations that transmits through each DGD segment, and by using tunable optical polarization rotators respectively located in gaps between the DGD segments, wherein the tunable optical polarization rotators include discrete-state tunable optical polarization rotators responsive to respective discrete-state control signals to produce two or more different discrete polarization rotations;
individually controlling each of the tunable optical polarization rotators to produce polarization mode dispersion of a first order and one or more higher orders on the light that transmits through the DGD segments and the tunable optical polarization rotators to negate PMD in the received optical WDM signal; andusing settings of the tunable optical polarization rotators and DGD values of the DGD segments to measure the PMD in the fiber link.
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39. A method for measuring optical polarization mode dispersion (PMD) in a fiber link, comprising:
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using a WDM demultiplexer to receive optical wavelength-division-multiplexed (WDM) signals at different WDM wavelengths from a fiber link and to separate the received optical WDM signals along different signal paths; splitting light received at the WDM demultiplexer at a location upstream from the WDM demultiplexer to produce an optical monitor signal to an optical monitor signal path separate from the different signal paths; tuning an tunable optical filter in the optical monitor signal path to a selected WDM channel to filter light of the optical monitor signal to transmit light within the selected WDM channel as a filtered optical monitor signal for the selected WDM channel; using a PMD instrument to process the filtered optical monitor signal for the selected WDM channel to measure PMD of the selected WDM by using differential group delay (DGD) segments separated from each other along the optical path and each exhibiting optical birefringence to effectuate a DGD between light of two orthogonal polarizations that transmits through each DGD segment, and by using tunable optical polarization rotators respectively located in gaps between the DGD segments, wherein the tunable optical polarization rotators include discrete-state tunable optical polarization rotators responsive to respective discrete-state control signals to produce two or more different discrete polarization rotations; and individually controlling each of the tunable optical polarization rotators to produce polarization mode dispersion of a first order and one or more higher orders on the light that transmits through the DGD segments and the tunable optical polarization rotators to negate PMD in the selected WDM channel; and using settings of the tunable optical polarization rotators and DGD values of the DGD segments to measure the PMD in the fiber link for the selected WDM channel. - View Dependent Claims (40, 41, 42, 43, 44, 45)
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Specification