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29 January 1985 Optoelectronic Switching
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Proceedings Volume 0517, Integrated Optical Circuit Engineering I; (1985)
Event: 1984 Cambridge Symposium, 1984, Cambridge, United States
An optoelectronic switch uses a photodetector as the switching element. The RF signal to be switched is delivered to the switching element as a modulation on an optical carrier. To place the optoelectronic switch in the on-state, an appropriate electrical bias is applied to the photodetector to allow it to function normally as a detector and recover the RF signal as the output. The off-state is established by changing or removing the electrical bias so that the photodetector no longer functions efficiently as a detector. Three types of photodetectors have been studied as optoelectronic switches; the homojunction photodiode (e.g. Si PIN), the heterojunction photodiode (e.g. InGaAs/InP) and the photoconductive detector (e.g. GaAs). Homojunction analogue optoelectronic matrix switches having isolation and crosstalk losses exceeding 80 dB and a baseband response of 100 MHz are available today. Experiments have shown that the heterojunction matrix can more than match this performance and also be switched in 30 ns. Photoconductive optoelectronic switches having switching times of 1 ns and responses to 1.3 GHz have been demonstrated. The high isolation and fast switching speeds possible with optoelectronic switches should open up many applications in the future, such as in satellite switched time division multiple access (SS-TDMA) systems, rapidly tuneable comb filters with envelope bandwidths in excess of 1 GHz as well as in fiber optic broadband integrated services to the home.
© (1985) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Elmer H. Hara "Optoelectronic Switching", Proc. SPIE 0517, Integrated Optical Circuit Engineering I, (29 January 1985);

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