Optimization of absorption of self electrooptic effect devices: a systems perspective

Abstract

For self electrooptic effect devices (SEEDs)1 and for some smart pixels,2 similar devices are used for optical modulators and detectors. Maximizing the contrast ratio or the difference in optical transmissivity (or reflectivity for reflection mode devices3) of the devices in the two states does not give optimum performance because sufficient light must be absorbed in the detector. We calculate the bit rate and signal tolerances for symmetric SEEDs (S-SEEDs) as a function of the absorption coefficients of the devices using a two-state absorption model. To maximize the system bit rate, we show that the optical transmissivities (or reflectivities) for a S-SEED for the two states should be ~58 and 0%. The calculated system bit rate agrees with measured results for a photonic ring counter to within 20%. We also discuss optimum absorptions for logic-SEEDs (L-SEEDs), currently the only demonstrated quantum well smart pixel technology,4 and for SEEDs that have electronic gain.2