Optical circulators
AssigneeJDS Uniphase Corporation
InventorsKok-Wai Chang, Kejian Guan, Yong Zhang
Life of this patent
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Abstract
An optical circulator having a dual fiber collimator and a single fiber collimator is described. The circulator provides a non-reciprocal functionality that directs input signals from a first fiber of the dual fiber collimator to the single fiber collimator. Input signals from the single fiber collimator are directed to a second fiber of the dual fiber collimator. The circulator includes birefringent wedges that change the angle of signals from the single fiber collimator to direct the signals to the second fiber of the dual fiber collimator. Because the circulator includes two collimators rather than three collimators, the circulator is more compact than a circulator having three collimators.
Claims18
A polarization independent optical circulator comprising:
- a first port for directing an optical signal to a second port the second port for directing an optical signal to a third port;
- polarization diversity means associated with the first, second and third ports for dividing the optical signal into two polarized optical signals and for combining two polarized optical signals of light, and for rotating a polarization of at least one of the two polarized optical signals;
- and
- means for aligning the signal from the first port to the second port and from the second port with the third port, for passing polarized optical signals traveling in a first direction having a first polarization without changing an optical path of the signals, and for changing an angle of the optical path for polarized optical signals traveling in a second direction having a second orthogonal polarization including:
- a first birefringent wedge;
- a second birefringent wedge;
- and
- a non-reciprocal optical element between the first birefringent wedge and the second birefringent wedge.
A polarization independent optical circulator comprising:
- a first port for directing an optical signal to a second port, the second port for directing an optical signal to a third port, the first and third ports supported on a single collimator;
- and the second port supported on a separate collimator;
- a first beam splitting walk off crystal and a second beam splitting walk off crystal for splitting the optical signal from the first port or second port into two orthogonally polarized signals and for combining two orthogonally polarized signals;
- a polarization rotator associated with each beam splitting walk off crystal for rotating a polarization of one of the two polarized optical signals passing from each of the beam splitting walk off crystals to match a polarization of the other of the two signals, and for rotating a polarization of one of the two signals passing into each of the beam splitting walk off crystals to be orthogonal to the other of the two signals;
- and,
- an assembly between the polarization rotators including a first birefringent wedge, a half wave plate, a Faraday rotator, and a second birefringent wedge for passing the two polarized optical signals in a first polarization state without affecting the angle of the signals in a first direction, and for changing the angle of the two polarized optical signals passing in a second polarization state between ports in a second direction.
Dependencies are inferred from the claim text.