RCE photodetectors based on VCSEL structures

We have fabricated top illuminated resonant cavity enhanced (RCE) detectors by partially removing top-mirror pairs of a vertical-cavity surface-emitting laser (VCSEL) structure by etching. The observed maximum quantum efficiency is 73% with a spectral full-width at half-maximum (FWHM) of about 1.7 nm. This particular RCE detector was fabricated by etching away 8 top-mirror pairs of a VCSEL structure, with 15.5 top-mirror pairs remaining. Spectral FWHMs as wide as 6.5 nm, with a peak efficiency of 36%, have been measured in the case of 4.5 top mirrors remaining. An increase in the 3-dB detector bandwidth up to 2.8 GHz is observed by reducing the active device diameter from 90 to 20 μm.