40 GHz monolithic integrated 1.3 /spl mu/m InGaAlAs-InP laser-modulator with double-stack MQW layer structure

Monolithic integrated DFB laser-modulator devices (EML) based on the double-type MQW stack are studied. First experimental results on optimization strategies for high-speed double stack EMLs are presented. The small-signal 3 dB bandwidth is improved, with respect to that previous device design, by more than a factor of two, up to the 40 GHz regime. This is done by decreasing the additional pin-junction capacitance in the EAM section by mesa width shrinkage and replacing the n-type InP substrate by a si-type one. Thus, the novel double-stack EML approach, fabricated in the InGaAlAs-InP material system, has the potential to meet the requirements of future 40 Gbps optoelectronic transceivers.