Optical Isolators
AssigneeLightel Technologies, Inc.
InventorsShyh-Chung Lin, Hongyu Hu
Life of this patent
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Abstract
An optical isolator device with minimized polarization mode dispersion includes a first polarization splitter/combiner, a non-reciprocal polarization rotator and a second polarization splitter/combiner. Only forward propagation of light is allowed to propagate in the device, with backward optical signal blocked due to non-reciprocal polarization rotation. The optical paths of o-ray and e-ray are arranged to achieve equal optical path lengths, which makes polarization mode dispersion minimal to nonexistent. When symmetrically configured, both polarization mode dispersion (PMD) and polarization dependent loss (PDL) become zero in principle.
Claims14
An optical isolator assembly, comprising:
- a first optical collimator;
- a first polarization beam splitter/combiner;
- a non-reciprocal polarization rotator;
- a second polarization beam splitter/combiner,
- a second optical collimator,
- wherein, with an optical signal received in the first optical collimator in a forward direction, a first incoming collimated optical beam emerges from the first optical collimator, passes through sequentially the first polarization beam splitter/combiner, the non-reciprocal polarization rotator and the second polarization beam splitter/combiner, and exits through the second optical collimator,
- wherein optical paths of two orthogonally polarized beams, an o-ray and an e-ray emerging from the first polarization beam splitter/combiner are configured to cross each other at a position, as projected on an incidence plane, before arriving at the second polarization beam splitter/combiner,
- wherein, with the optical signal received in the first optical collimator in the forward direction, polarizations of the two orthogonally polarized beams, the o-ray and the e-ray emerging from the first polarization beam splitter/combiner, are configured so that the o-ray from the first polarization beam splitter/combiner turns into an e-ray in the second polarization beam splitter/combiner and the e-ray from the first polarization beam splitter/combiner turns into an o-ray in the second polarization beam splitter/combiner,
- wherein, with another optical signal received in the second optical collimator in a reverse direction, a second incoming collimated optical beam from the second optical collimator passes through sequentially the second polarization beam splitter/combiner, the non-reciprocal polarization rotator and the first polarization beam splitter/combiner, and emerge as two angularly deviated orthogonally polarized beams due to the non-reciprocal polarization rotator, and
- wherein the two angularly deviated orthogonally polarized beams cannot be coupled into the first optical collimator.
Dependencies are inferred from the claim text.