Comparison of electroabsorption in tensile‐strained and lattice‐matched GaAs(P)/AlGaAs quantum wells

The performance of tensile‐strained GaAsP/AlGaAs multiple‐quantum well (MQW) reflection modulators is compared to that of similar lattice‐matched GaAs/AlGaAs devices operating in the same wavelength range. The tensile‐strained modulators utilize ∼95 Å GaAs_0.92P_0.08 quantum wells, which are designed to make use of the field‐induced merging of electron‐to‐light‐hole (e‐lh) and electron‐to‐heavy‐hole (e‐hh) excitonic absorption edges achievable in tensile strained wells. Unstrained ∼46 Å GaAs quantum wells yielding similar excitonic gaps are utilized in the lattice‐matched devices, but the strained and unstrained modulators are otherwise virtually identical. Room‐temperature differential reflection spectra reveal increased modulation depths at low drive voltages in the tensile‐strained devices, consistent with electroabsorption enhancements expected in these structures from merging of the elh and ehh transitions.