Predicted performance of Franz-Keldysh effect optical reflection modulators and comparisons with similar multiple quantum well-based devices

In the paper the electroabsorption and electrorefraction spectra are calculated for GaAs, InGaAsP and InGaAs. These are compared both with experimental results and data from the literature giving very good agreement. From these calculations the behaviour of simple reflection modulators operating at 885 nm, 1.32 μm and 1.76 μm is quantified for a 3 dB insertion loss. This produces contrasts (on:off) of approximately 3 dB at -30 V bias for all three semiconductors above. By using a Fabry-Perot cavity formed by the end faces of the modulator devices these contrasts are shown to increase to 20 dB for GaAs and InGaAsP, and 6.9 dB for InGaAs at the same bias. This potential performance is compared to multiple quantum well devices which also make use of cavity effects