INTEGRATED WAVEGUIDE P-I-N PHOTODETECTOR.

A p-i-n photodetector in In//0//. //5//3Ga//0//. //4//7As/InP integrated at the end of a ridge waveguide in n** minus : InP/n** minus :InP is reported. In the waveguide, an average propagation loss of 3 dB/cm at 1. 15 mu m was measured with a coupling loss of 2 dB and a reflection loss of 3 dB. For optical evaluation of the waveguide-detector, 1. 15- mu m light from a He-Ne laser was coupled into the waveguide and the detected photocurrent was measured as a function of the input light intensity with reverse bias as a parameter. The response of the detector was linear with intensity. Typically, a photocurrent of 11 mu A was measured for an input light intensity of 56 mu W falling on the waveguide. Taking into account coupling, reflection and propagation losses, it is estimated that 85% of the guided light was absorbed by the photodetector. The device had a 3-dB bandwidth of 500 MHz when light from a 1. 3- mu m semiconductor laser source was coupled into the waveguide.