Patent ID: 8786937
Filing Date: 2014-07-22
Classification: H04B

Abstract:
1. 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.