Polarization mode dispersion compensation via an automatic tracking of a principal state of polarization
First Claim
1. In an optical transmission system, a polarization mode dispersion (PMD) compensation arrangement comprising:
- a polarization beam splitter (PBS) comprising a first polarization axis for directing first linearly polarized components of a dithering optical signal received by the PMD compensation arrangement onto a first output path, and a second polarization axis for directing second orthogonally linearly polarized components of the received dithering optical signal onto a second output path for transmission as an output signal from the PMD compensation arrangement;
a polarization controller (PC) coupled to receive the dithering optical signal received by the PMD compensation arrangement including first and second principal states of polarization (PSPs) and PMD distortion, the PC transforming the first and second PSPs into linearly polarized components and being responsive to a feedback control signal for aligning the linearly polarized first and second PSPs to the first and second polarization axes of the PBS for transmission to the PBS; and
compensation control means responsive to both the dithering optical signal received by the PMD compensation arrangement and the first polarized components on the first output path from the PBS for measuring interference characteristics of the PSPS, and generating the feedback control signal to the PC for aligning each of the linearly polarized PSPs with a separate one of the first and second polarization axes of the PBS based on the measured interference characteristics.
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Accused Products
Abstract
A polarization mode dispersion (PMD) compensator compensates for PMD in an optical signal by an automatic tracking of a principal state of polarization (PSP). A polarization controller (PC) receives a dithering optical signal including first and second principal states of polarization (PSPs) and PMD distortion received by the PMD compensator. The PC transforms the first and second PSPs into linearly polarized components, and is responsive to a feedback control signal for aligning the linearly polarized first and second PSPs to first and second polarization axes of the PBS, respectively. A polarization beam splitter (PBS) directs first polarized components of the received dithering optical signal onto a first output path, and directs second orthogonally polarized components of the received dithering optical signal onto a second output path for transmission as a PMD compensator output signal. A compensation control arrangement is responsive to both the received dithering optical signal and the first polarized components from the PBS for measuring interference characteristics of the two PSPs, and for generating the feedback control signal to the PC for aligning each of the PSPs with a corresponding one of first and second polarization axes of the PBS based on the measured interference characteristics.
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Citations
34 Claims
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1. In an optical transmission system, a polarization mode dispersion (PMD) compensation arrangement comprising:
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a polarization beam splitter (PBS) comprising a first polarization axis for directing first linearly polarized components of a dithering optical signal received by the PMD compensation arrangement onto a first output path, and a second polarization axis for directing second orthogonally linearly polarized components of the received dithering optical signal onto a second output path for transmission as an output signal from the PMD compensation arrangement; a polarization controller (PC) coupled to receive the dithering optical signal received by the PMD compensation arrangement including first and second principal states of polarization (PSPs) and PMD distortion, the PC transforming the first and second PSPs into linearly polarized components and being responsive to a feedback control signal for aligning the linearly polarized first and second PSPs to the first and second polarization axes of the PBS for transmission to the PBS; and compensation control means responsive to both the dithering optical signal received by the PMD compensation arrangement and the first polarized components on the first output path from the PBS for measuring interference characteristics of the PSPS, and generating the feedback control signal to the PC for aligning each of the linearly polarized PSPs with a separate one of the first and second polarization axes of the PBS based on the measured interference characteristics. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14)
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15. In an optical transmission system, a polarization mode dispersion (PMD) compensation arrangement comprising:
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an optical tap responsive to the reception of a dithering optical signal from a remote transmitter including polarization mode dispersion and first and second orthogonal principal states of polarization (PSPs) for directing a first portion of the received dithering optical signal onto a first output path and a second portion of the received dithering optical signal onto a second output path; a polarization beam splitter (PBS) coupled to receive the second portion of received dithering optical signal from the optical tap, the PBS comprising a first polarization axis for directing first polarized components onto a first output path, and a second polarization axis for directing second orthogonally polarized components onto a second output path for transmission as an output signal from the PMD compensation arrangement; and compensation control means responsive to both the first portion of the received dithering optical signal on the first output path from the optical tap and the first polarized components on the first output path from the PBS for measuring interference characteristics of the two principal states of polarization for aligning each of the principal states of polarization in the received dithering optical signal on the second output path from the optical tap with the corresponding first and second polarization axes of the PBS based on the measured interference characteristics. - View Dependent Claims (16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28)
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29. A method of providing polarization mode dispersion (PMD) compensation in an optical transmission system comprising the steps of:
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(a) receiving a dithering optical signal including first and second orthogonal principal states of polarization (PSPs) that have been subjected to polarization mode dispersion; (b) transforming the first and second orthogonal (PSPS) in the received dithering optical signal from step (a) into orthogonal first and second linearly polarized components in a polarization controller (PC); (c) directing all linearly polarized components which are aligned with a first polarization axis of a polarization beam splitter (PBS) to a first optical input of a compensation control means and directing all linearly polarized components which are aligned with a second polarization axis of the polarization beam splitter (PBS) as an optical output signal to a remote user device; (d) measuring interference characteristics and amplitude fluctuations in polarized components obtained from via the first polarization axis of the PBS in step (c) in the compensation control means for generating a feedback control signal to the PC; and (e) causing the PC to realign the first and second linearly polarized components to match the first and second polarization axes of the PBS in response to the feedback control signal from step (d). - View Dependent Claims (30, 31, 32, 33, 34)
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Specification