Six-port and five-port receivers for UWB and optical communications

Some achievements on multiport direct conversion receivers at microwave and optical frequencies are reported. Several sixport junctions with full UWB band (3.1-10.6 GHz) coverage will be presented and compared which, due to their low imbalances, allow to develop a six-port direct conversion receiver with analog I/Q recovery for the complete UWB band. On the optical side, six-port based receivers have found wide acceptance as coherent receivers for 100Gbit/s communications based in QPSK and higher order modulations. Results will be presented showing six-port and five-port, monolithically integrated coherent receivers. Six-port receivers are based in 90° hybrids with analog I/Q recovery, while five-port receivers are based in 120° couplers with digital I/Q regeneration, which can offer superior hardware compensation capabilities.