Picosecond photoconductive sampling with nanosecond carrier lifetimes using an integrated inductive loop

Autor: Frank W. Wise, Richard C. Compton, Andrew C. Davidson
Rok vydání: 1995
Předmět:
Zdroj: Applied Physics Letters. 66:2259-2261
ISSN: 1077-3118
0003-6951
DOI: 10.1063/1.113185
Popis: High-speed optical sampling of electrical signals is usually carried out by either electrooptic1 or photoconductive2 sampling. These methods are capable of sub-picosecond temporal resolution and have found widespread use in the characterization of optoelectronic devices, but suffer certain drawbacks. To achieve responses in the one-picosecond regime3,4, photoconductive techniques rely on short-lifetime material such as low-temperature-grown or ion-damaged GaAs. Short-lifetime material may be well-suited for devices such as photodetectors, but more complicated integrated circuits generally use high-quality, long-lifetime material. Photoconductive measurements on such circuits can be accomplished by selectively ion-damaging the desired region, but this requires additional processing steps. The method of electro-optic sampling5,6 is capable of sub-picosecond resolution but has more complicated optical requirements and several limitations. With substrate probing, the substrate must exhibit the Pockels effect and must be transparent to the probe beam. With external-crystal probing, a sufficiently small electro-optic crystal is required and must be positioned within the electric field of the signal to be sampled. This paper describes a new high-speed method of photoconductive sampling intended to overcome these drawbacks. The method relies on electromagnetic coupling to generate the time derivative of a signal; a slow sampling gate fabricated on long-lifetime material then integrates the coupled signal to produce the desired waveform.
Databáze: OpenAIRE
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