Demonstration of enhanced performance of an InP/InGaAs heterojunction phototransistor with a base terminal

The optical gain and the small-signal frequency response of an InP/InGaAs heterojunction phototransistor (HPT) with a base terminal are investigated in detail for the first time. When operated under an optimally chosen external base current, the optical gain is enhanced more than five times over that of the same device operated as a two-terminal device, over a 17-dB range of input optical power. The small-signal 3-dB bandwidth of the three-terminal device is enhanced 15 times over that of the two-terminal device over the same range of input optical power. For a pseudorandom NRZ bit stream at 100 Mb/s, a clear eye opening is observed at an incident optical power of -33 dBm (500 nW).<
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