In this work, we present a novel photonic package for high-power photoreceiver modules operating within the E-band (60–90 GHz). The developed Kovar package features a compact size of only 6×3.5×2 cm3 and comprises an optical single-mode fiber (SMF) input, DC bias supply connections and a WR-12 output for coupling out of the radio frequency (RF) signal. As integration platform, a RF laminate submount with implemented planar bias-T based upon grounded coplanar waveguide (GCPW) transmission line circuitry is used for efficient mmW propagation, concluding in a GCPW-to-WR-12-transition. Finite element method (FEM) simulations have been carried out to analyze the frequency range of interest. Besides applied adhesive and wire bonding approaches for assembly inside the package, the RF submount exhibits sections for hybrid integration of single components, e.g. of a high-frequency waveguide photodiode. Optionally, up to two high-electron-mobility-transistor (HEMT) power amplifiers can be integrated within the GCPW circuitry. In addition, the RF laminate is mounted on a brass platform. For uniform thermal expansion within the module, a Peltier element is integrated. Concerning the saturation output power of given HEMT amplifiers, e.g. in the order of +17.5 dBm, corresponding power levels are achievable for packaged devices. For instance, an output RF power of only −19.5 dBm within the 71–76 GHz band is required from the photodiode in conjunction with two cascaded HEMT amplifiers, which results in a total gain of ~37 dB. A small series of the introduced device has been already fabricated. First experimental achievements with in-house fabricated modules will be presented.
Coupling single-mode fiber to uniform and symmetrically tapered thin-film waveguide structures using gadolinium gallium garnet
