Here, we report on planar photonic transmitters employing high-speed 1.55 µm photodiodes. Within the 200-300 GHz band, the device exhibits a 6-dB bandwidth along with a polarization penalty of ~2.2 dB. Besides, the chip area is reduced thanks to a novel integration approach in the antenna structure.

In this work, we present novel integrated Ψ-type photonic polarization diversity receivers (PPDRs), comprising two high-frequency 1.55 μm photodiodes (PDs) applicable in wireless radio-over-fiber (RoF) communication links. Therefore, geometries in the overall optical beam splitter (OBS) output section, e.g. optical mode-guiding stripe height, gap between the optical waveguides (WGs), WG widths and coupling length, are considered to obtain high polarization diversity for the developed PPDRs. Moreover, we demonstrate first experimental achievements based on the coupling length variation. In comparison to a conventional 3-dB Y-coupler-integrated device, the experimental results show a polarization-dependent behavior of the PPDR with a maximum polarization dependent loss (PDL) of >3 dB (e.g. measured at the WG-PDs) due to the integrated Ψ-type OBS output section. Taking further geometry parameters of the PPDR into consideration, an increased PDL is expected for the monolithically integrated WG-PDs.