MEASUREMENT OF MODULATION SATURATION INTENSITY IN STRAIN-BALANCED, UNDEFECTED INGAAS/GAASP MODULATORS OPERATING AT 1.064-MU-M

We measure high modulation saturation intensities in both strain-relaxed InGaAs/GaAs multiple-quantum-well (MQW) modulators (107 kW/cm2) and strain-balanced InGaAs/GaAsP MQW modulators (31 kW/cm2)operating at 1.064 mum, measured with a Nd:YAG laser. This compares with 16 kW/cm2 for GaAs/Al0.3Ga0.7As thin barrier MQW modulators and 65 kW/cm2 for GaAs/Al0.02Ga0.98As shallow MQW modulators operating near 850 nm (reflection modulators). The advantage of the strain-balanced system is that it results in an undefected material with sharper excitonic features and better morphology compared to the strain-relaxed system. This study shows that the InGaAs/GaAsP system may be used to obtain long wavelength operation with these advantages without incurring an unreasonable penalty for high power operation due to the higher barriers.