A family of ultrafast photodetectors and photoreceivers, based on evanescently coupled photodiodes, is described. The waveguide-integrated detectors are monolithically integrated with HEMTs, employing semi-insulating optical waveguides on a semi-insulating InP:Fe substrate. The integration scheme is explained and demonstrated by several examples of broadband and narrowband photodetectors, balanced detectors and photoreceivers, focussing on applications at data rates from 80 to ∼160 Gbit/s.