Silicon depletion modulators with enhanced slab doping

A silicon carrier-depletion modulator, comprising:

• a waveguide comprising a core of a first height and a slab of a second height less than the first height, the core including a first core region doped to a core doping level of a first conductivity type and a second core region doped a second conductivity type opposite the first conductivity type,
• wherein the slab includes a first slab region doped the first conductivity type, a second slab region doped the first conductivity type, and a third slab region, and
• wherein the second and third slab regions are between the first slab region and the first core region, the third slab region is between the second slab region and the first core region, and wherein a first doping level of the first slab region is greater than a second doping level of the second slab region, and the second doping level of the second slab region is greater than a third doping level of the third slab region and the core doping level.