The high-speed operation of an optical tap on InP waveguides using an InGaAs p-i-n photodetector has been demonstrated. For a 300- mu m-long tap that samples 19% of the light propagating in a 7- mu m-wide waveguide, the response time is 50 ps with a 1-V reverse bias. This speed is limited by the RC time constant. The taps require a single epitaxial growth and can be readily integrated with directional coupler switches and other optoelectronic devices for multi-GHz optical signal processing.<<ETX>>