Advances in traveling-wave electroabsorption modulators for analog applications

We review the design and fabrication of the traveling wave (TW) electrode for the EAM for high speed and high power operation. In one approach, EAMs with improved saturation properties have been demonstrated via the lowering of the hole barrier by applying appropriate strain at the well/barrier interface. An alternate approach to enhance the saturation power of the quantum well modulator is via the use of a barrier step inside the well to suppress the onset of the red shift in the quantum-confined Stark effect to a higher electric field. In these approaches, however, the saturation power is optimized without incorporating the modulation frequency considerations.