Patent ID: 6956697
Filing Date: 2005-10-18
Classification: G02B

Abstract:
1. A circulator device for launching on optical signal into an optical device and for outputting the optical signal after modification by the optical device comprising: an input port for inputting the optical signal; a polarization beam splitter optically coupled to the input port for separating the optical signal into first and second orthogonally polarized sub-beams; a first polarization rotator for rotating the polarization of at least one of the first and second orthogonally polarized sub-beams of the optical signal, so that both sub-beams of the optical signal have the same polarization; polarization beam directing means for directing optical sub-beams with a first polarization along one set of paths, and for directing optical sub-beams with a second polarization along another set of paths; non-reciprocal polarization rotating means for rotating the polarization of optical sub-beams traveling in a first direction therethrough, while having no overall effect on the polarization of optical sub-beams traveling in a second direction therethrough; a first input/output port for outputting the first sub-beam of the optical signal with the first polarization, and for inputting a first sub-beam of the modified optical signal with the first polarization, whereby the first sub-beam of the modified optical signal travels back through the non-reciprocal polarization rotating means and the polarization beam directing means; a second input/output port for outputting the second sub-beam of the optical signal with the first polarization, and for inputting a second sub-beam of the modified optical signal with the first polarization, whereby the second sub-beam of the modified optical signal travels back through the non-reciprocal polarization rotating means and the polarization beam directing means; a second polarization rotator for rotating the polarization of at least one of the first and second sub-beams of the modified optical signal, so that the sub-beams of the optical signal have orthogonal polarizations; a polarization beam combiner optically coupled to the output port for combining first and second orthogonally polarized sub-beams of the modified optical signal; and an output port for outputting the modified optical signal; whereby light entering the first and second input/output ports with the second polarization will be directed away from the input and output ports.