Performance of In/sub 0.53/Ga/sub 0.47/As and InP junction field-effect transistors for optoelectronic integrated circuits. II. Optical receiver analysis

For pt.I see ibid., p.957-65. The receiver under study consists of an In/sub 0.53/Ga/sub 0.47/As p-i-n photodiode and an In/sub 0.53/Ga/sub 0.47/As or InP JFET transimpedance preamplifier. For this study, the two-region JFET model developed in pt.I is extended to include the dependence of receiver noise on transistor design. The authors find that the channel doping should be small enough to avoid shot noise due to the onset of tunneling current between the gate and drain, where as it must be large enough to provide adequate gain. Also, they show that the receiver sensitivity is not a strong function of input FET gate width. Hence, for circuits with high device density, the gate width and the FET power dissipation can be an order of magnitude less than for those structures currently investigated, thereby incurring a sensitivity penalty of only 1 dB as against wide-gate transistors. Optimized receivers using either InP or In/sub 0.53/Ga/sub 0.47/As JFETs are found to have comparable sensitivities.<
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