Picosecond photoconductive devices for 10 Gbit/s optoelectronic switching

Semiconductor materials with a high density of recombination and trapping centers exhibit extremely short carrier lifetimes in the order of 1 to 100 ps and have been the base for the development of high speed optoelectronic switches. These devices are activated by picosecond laser pulses and can be driven nearly free of jitter with respect to the optical excitation pulses. They show some unique properties as picosecond risetimes and response times and can be operated within a relatively high dynamical range (10-5 to 10 sub 4 V) (0.00001 to 0.0001 V). A review is given on the wide field of possible applications of the ultrafast photoconductive switches. They can be used as photodetectors for picosecond light pulses as well as sampling gates for the characterization of high speed electronic and optoelectronic devices. In some experiments which are discussed more in detail the author demonstrates the capability of this type of photoconductive switches for the generation of picosecond infrared pulse trains in laser diodes and for the generation of high-bit rate electrical codes for use in Gbit/s optical communication and sensing systems, for logical switching and for testing purposes of high speed electronic instrumentations.