High-speed >90% quantum-efficiency p–i–n photodiodes with a resonance wavelength adjustable in the 795–835 nm range

We report GaAs/AlGaAs-based high-speed, high-efficiency, resonant cavity enhanced $\mathrm{p–i–n}$ photodiodes. The devices were fabricated by using a microwave-compatible fabrication process. By using a postprocess recess etch, we tuned the resonance wavelength from 835 to 795 nm while keeping the peak efficiencies above 90%. The maximum quantum efficiency was 92% at a resonance wavelength of 823 nm. The photodiode had an experimental setup-limited temporal response of 12 ps. When the system response is deconvolved, the 3 dB bandwidth corresponds to 50 GHz, which is in good agreement with our theoretical calculations.