We report an optical upconversion device that converts input 1.5μm light to output 0.87μm light with a built-in gain mechanism. The device consists of an InGaAs∕InP heterojunction phototransistor (HPT) integrated with a GaAs∕AlGaAs light-emitting diode (LED) by wafer fusion process. Incoming 1.5μm optical radiation is absorbed by the HPT, generating an amplified photocurrent. The resultant photocurrent drives the LED that emits at 0.87μm, which could be detected by a conventional silicon charge-coupled device. Upconversion is demonstrated at room temperature with a gain of 20 from the HPT and an overall external upconversion efficiency of 0.07W∕W.
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Luo et al. (2006) studied this question.
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