Dual-polarization QPSK demodulator
AssigneeFinisar Corporation
InventorsFan Chen, Fahua Lan, Huiping Li, Kevin Dapeng Zhang
Life of this patent
Estimating the term…
Abstract
In an embodiment, a DP-QPSK demodulator includes first, second and third polarization beam splitters (“PBSs”) and first, second and third half waveplates (“HWPs”). The first HWP is positioned to receive an output of the first PBS. The second PBS is positioned to receive an output of the first HWP. The second HWP is positioned to receive an output of the second PBS. The third PBS is positioned to receive an output of the second HWP. The third HWP is positioned to receive an output of the third PBS.
Claims20
A dual-polarization quadrature phase shift keyed (“DP-QPSK”) demodulator comprising:
- a first polarization beam splitter that defines two input paths and four output paths;
- a first half waveplate positioned after the first polarization beam splitter;
- a second polarization beam splitter positioned after the first half waveplate, wherein the second polarization beam splitter defines four input paths and eight output paths;
- a second half waveplate positioned after the second polarization beam splitter;
- a third polarization beam splitter positioned after the second half waveplate, wherein the third polarization beam splitter defines eight input paths and four output baths;
- and
- a third half waveplate positioned after the third polarization beam splitter,
- wherein the first polarization beam splitter, the first half waveplate, the second polarization beam , the second half wavesplate the third polarization beam splitter, and the third half waveplate are positioned linearly one after the other.
An optoelectronic module comprising:
- a dual-polarization quadrature phase shift keyed (“DP-QPSK”) demodulator including:
- a first polarization beam splitter that defines two input paths and four output paths;
- a first half waveplate positioned after the first polarization beam splitter;
- a second polarization beam splitter positioned after the first half waveplate, wherein the second polarization beam splitter defines four input paths and eight output paths;
- a second half waveplate positioned after the second polarization beam splitter;
- a third polarization beam splitter positioned after the second half waveplate, wherein the third polarization beam splitter defines eight input paths and four output paths;
- and
- a third half waveplate positioned after the third polarization beam splitter, wherein the first polarization beam splitter, the first half waveplate, the second polarization beam splitter, the second half waveplate, the third polarization beam splitter, and the third half waveplate are positioned linearly one after the other;
- a plurality of optical detectors positioned to receive a plurality of optical signals output by the DP-QPSK demodulator and configured to convert the plurality of optical signals to a plurality of electrical signals;
- and
- a digital signal processor electrically coupled to respective outputs of the plurality of optical detectors.
Dependencies are inferred from the claim text.