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US 6,782,211 B1Granted
Cross polarization interface canceler
OwnerMark T. Coreinventor
Life of this patent
Estimating the term…
Abstract
Implemented in both coherent and non-coherent optical systems, a receiving device including a cross polarization interference canceler (XPIC) is described. For these embodiments, the XPIC optimizes bandwidth efficiency of an optical communication link by enabling the reconstruction of two optical signals transmitted with generally orthogonal polarization states and routed over a single fiber optic transmission medium in the same frequency band.
Claims37
A system comprising:
- a transmitting device to modulate orthogonally polarized optical carriers with independent information bearing waveforms;
- and
- a receiving device including (i) a cross polarization interference canceler that comprises a plurality of optical elements each supporting a transfer function to collectively mitigate cross polarization interference and to reconstruct the information bearing waveforms recovered from the orthogonally polarized optical carriers and (ii) a plurality of receivers each to receive an optical signal from the cross polarization interference canceler.
Implemented to receive an incoming optical signal, a receiving device comprising:
- a first polarization beam splitter to separate a received optical signal field of the incoming optical signal into orthogonally polarized components;
- and
- a cross polarization interference canceler following the first polarization beam splitter, the cross polarization interference canceler comprises a plurality of outputs and a plurality of elements each supporting a transfer function, each output of the plurality of outputs being the sum of at least two element outputs.
A receiving device implemented to receive an incoming optical signal, a receiving device comprising:
- a first polarization beam splitter to separate a received optical signal field of the incoming optical signal into orthogonally polarized components;
- and
- a cross polarization interference canceller (XPIC) in communication with the first polarization beam splitter, the XPIC being an electrical intermediate frequency (IF) XPIC.
A method comprising:
- receiving an optical signal over a single fiber optic transmission medium, the optical signal being one or more polarized field components independently modulated with independent information bearing waveforms;
- and
- processing the optical signal by (i) separating the optical field of the optical signal into orthogonally polarized field components, (ii) routing each of the orthogonally polarized field components to a coherent optical receiver to produce a first output and a second output, and (iii) transmitting the first and second outputs to a cross polarization interference canceller (XPIC).
A method comprising:
- receiving an optical signal over a single fiber optic transmission medium, the optical signal being at least two polarized field components independently modulated with independent information bearing waveforms;
- and
- mitigating cross polarization interference associated with the at least two modulated polarized field components to reconstruct the information bearing waveforms using a plurality of matrix coefficients being complex values to apply both amplitude scaling and phase shifting to the at least two modulated polarized field components.
A method comprising:
- receiving at least two optical signals with independent information bearing waveforms over a single fiber optic transmission medium, the at least two optical signals having been transmitted with generally orthogonal polarization states;
- and
- mitigating cross polarization interference associated with the at least two optical signals to reconstruct the information bearing waveforms, mitigation of the cross polarization interference is accomplished through a matrix multiplication using a cross polarization interference canceler that produces the recovered signals with the minimum mean square error (MMSE) relative to the desired transmitted signals.
A method comprising:
- receiving an optical signal over a single fiber optic transmission medium, the optical signal being one or more polarized field components independently modulated with independent information bearing waveforms;
- and
- processing the optical signal by (i) separating the optical field of the optical signal into orthogonally polarized field components, (ii) processing the orthogonally polarized field components by an optical cross polarization interference canceller (XPIC), (iii) routing outputs of the optical XPIC to coherent optical receivers that convert the outputs into corresponding current outputs, and (iv) demodulating the current outputs to reconstruct baseband waveforms associated with the received optical signal.
A method comprising:
- receiving at least two optical signals with independent information bearing waveforms over a single fiber optic transmission medium, the at least two optical signals having been transmitted with generally orthogonal polarization states;
- and
- eliminating cross polarization interference associated with the at least two optical signals to reconstruct the information bearing waveforms, the elimination of the cross polarization interference is accomplished through matrix multiplication using a diagonalizer cross polarization interference cancellation network being a general inverse of a transmission matrix associated with the transmitter and the single fiber optic transmission medium.
Dependencies are inferred from the claim text.