High-speed high-efficiency photodetectors for short pulse applications

Resonant cavity enhanced (RCE) photodetectors are promising candidates for applications where high-speed high-efficiency photodetection is desirable. In RCE devices, the active device structure is placed inside a Fabry-Perot resonant microcavity that causes a large enhancement of the resonant optical field. The increased optical field allows the design of thinner photodetectors while simultaneously increasing the quantum efficiency at the resonant wavelengths. We present measurements of quantum efficiency of GaAs/AlGaAs RCE p-i-n photodiodes designed for near-unity quantum efficiency. The bandwidth-efficiency product is in excess of 50 GHz. We consider two applications, namely optical communications and quantum optical measurements employing pulsed lasers which would benefit from a wider peak response than that is readily accomplished using RCE detection.