Integrated polarization diversity front end optics

The integration of a polarization-diversity receiver front-end suitable for balanced detection has been realized by the hybrid combination of a 3-dB directional coupler and a thin-film polarization beam splitter (PBS) fabricated on silica-based waveguides. Insertion losses, excluding the intrinsic loss of the coupler, were 1 and 1.2 dB for TE- and TM-polarizations, respectively. The polarization cross talk was less than -23 dB.<
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