In this paper, we review our research efforts on resonant cavity enhanced (RCE) high-speed high-efficiency p-i-n and Schottky photodiodes (PDs) operating in the 1(st) optical communication window. Using a microwave compatible planar fabrication process, we have designed and fabricated GaAs based RCE photodiodes. For RCE Schottky type photodiodes, we have achieved peak quantum efficiencies of 50% and 75% with semi-transparent (Au) and transparent (indium-tin-oxide) Schottky layers, respectively. Along with 3-dB bandwidths of 50 and 60 GHz, these devices exhibit bandwidth-efficiency (BWE) products of 25 GHz and 45 GHz respectively. For RCE p-i-n type photodiodes, we have fabricated and tested widely tunable devices with 92% quantum efficiency, along with a 3-dB bandwidth of 50 GHz, resulting in a 46 GHz BWE performance. These results correspond to the highest detector performances reported for vertically illuminated Schottky and p-i-n PDs in scientific literature.