Independently variable first and second order polarization mode dispersion compensator
AssigneeMassachusetts Institute of Technology
InventorPoh-Boon Phua
Life of this patent
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Abstract
A PMD compensator or generator includes one module for adjusting first order PMD without altering second order PMD (FOnSO module), and another module for adjusting second order PMD without altering first order PMD (SOnFO module). The modules enable separate compensation of first and second order PMD. First order PMD can be measured and compensated in a feedforward manner, while second order PMD can be compensated in a feedback manner. Both first and second order PMD can be compensated in a feedforward manner. The modules also enable separate generation of first and second order PMD, and can be used in a completely deterministic manner to achieve the desired PMD.
Claims32
An apparatus for compensating or generating polarization mode dispersion (PMD) for an optical fiber, comprising:
- means for separately controlling the magnitude of the first and second order PMD in a lightwave signal, the means for controlling the magnitude of the first order PMD including
- first means for producing a first portion of the desired first order PMD magnitude and a first determined amount of second order PMD,
- second means for producing a second portion of the desired first order PMD magnitude and a second determined amount of second order PMD, and
- first tuning means for adjusting a coupling of the first means and second means to produce the full amount of desired first order PMD magnitude and to produce no second order PMD, and
- means for controlling the direction of the first and second order PMD in the lightwave signal.
A method for compensating or generating polarization mode dispersion (PMD) for an optical fiber, comprising:
- separately controlling the magnitude of the first and second order PMD in a lightwave signal, by
- providing a first means for producing a first portion of the desired first order PMD magnitude and a first determined amount of second order PMD,
- providing a second means for producing a second portion of the desired first order PMD magnitude and a second determined amount of second order PMD, and
- adjusting a coupling of the first means and second means to produce the full amount of desired first order PMD magnitude and to produce no second order PMD, and
- controlling the direction of the first and second order PMD in the lightwave signal.
An apparatus for compensating polarization mode dispersion (PMD) in a lightwave signal, comprising:
- a first module for compensating first order PMD without affecting second order PMD, including
- first and second portions, each for producing second order PMD alterations that cancel each other, and
- a tuner for adjusting the coupling of the first and second portions so that each of the first and second portions produces half of the first order PMD alteration, and
- a second module for compensating second order PMD without affecting first order PMD, wherein the first and second modules are separately controlled.
An apparatus for generating polarization mode dispersion (PMD) in a lightwave signal, comprising:
- a first module for generating first order PMD without affecting second order PMD, including
- first and second portions, each for producing second order PMD alterations that cancel each other, and
- a tuner for adjusting the coupling of the first and second portions so that each of the first and second portions produces half of the first order PMD alteration, and
- a second module for generating second order PMD without affecting first order PMD, wherein the first and second modules are separately controlled.
A module for altering first order polarization mode dispersion (PMD) without altering second order PMD in a lightwave signal, comprising:
- first and second portions, each for producing second order PMD alterations that cancel each other, and
- a tuner for adjusting the coupling of the first and second portions so that each of the first and second portions produces half of the first order PMD alteration.
A module for altering second order polarization mode dispersion (PMD) without altering first order PMD in a lightwave signal, comprising:
- first and second portions, each for producing first order PMD alterations that cancel each other, each of the first and second portions including two fixed differential group delay (DGD) segments and a portion tuner for coupling the two fixed DGD segments, and
- a module tuner for adjusting the coupling of the first and second portions so that each of the first and second portions produces half of the second order PMD alteration,
- wherein the module tuner and each of the portion tuners are substantially identically tuned.
A module for altering second order polarization mode dispersion (PMD) without altering first order PMD in a lightwave signal, comprising:
- first and second portions, each for producing first order PMD alterations that cancel each other,
- a module tuner for adjusting the coupling of the first and second portions so that each of the first and second portions produces half of the second order PMD alteration, and
- two fixed phase-plates for respectively coupling the first and second portions to the module tuner, the module tuner and two fixed phase-plates forming a polarization controller.
Dependencies are inferred from the claim text.