InGaAs/InAlAs quantum wells for 1.3 micron electro-absorption modulators on GaAs substrates

Optical modulators are of great importance in fiber communication systems, and semiconductor modulators have distinct advantages over other materials. For modulators operating at 1.3;Growth of InGaAs/InAlAs MQW structures superposed on a low temperature grown step-graded InAlAs buffer is presented. Structural and optical properties of the InAlAs buffer and electro-optical properties of the MQW structures are evaluated and analyzed. Waveguide modulators employing this InAlAs buffer on GaAs substrates have been designed and fabricated.;InAlAs was selected as a relaxed step-graded buffer material to relax the strain between the well material ;Efficient electroabsorption modulation has been demonstrated on MQW structures employing step-graded InAlAs buffers grown at 350;Electro-absorption properties of MQW structures on GaAs are also analyzed theoretically. Theoretical predictions of the quantum confined Stark shifts based on the envelope function, effective well width method and calculated electric field, are in good agreement with experimental data under relatively low field (smaller than ;Waveguide modulators for broad band analog applications have been designed, fabricated and evaluated by other researchers in the same project. Discussions on these issues are presented. Transmission measurements demonstrate an optimum detuning energy in good agreement with the material figure of merit prediction. A 3-dB electrical bandwidth in excess of 20GHz and a saturation optical power in excess of 18mW is also demonstrated. This is the first report of modulation in the microwave range on 1.3...