Electro-refraction modulator with a regrown p-n junction

A system, comprising:

• a processor;
• a memory, coupled to the processor, that stores a program module, which, during operation, is executed by the processor;
• and
• an integrated circuit, wherein the integrated circuit includes:
• a substrate;
• a buried-oxide (BOX) layer disposed on the substrate;
• and
• a semiconductor layer, wherein the semiconductor layer includes an optical modulator;
• wherein the optical modulator includes an instance of a stack including:
• an outer n-type layer having a minimum n-type doping level, an intermediate n-type layer having an intermediate n-type doping level that is greater than the minimum n-type doping level, a junction n-type layer having a maximum n-type doping level that is greater than the intermediate n-type doping level, a junction p-type layer having a maximum p-type doping level, an intermediate p-type layer having an intermediate p-type doping level that is less than the maximum p-type doping level, and an outer p-type layer having a minimum p-type doping level that is less than the intermediate p-type doping level;
• and
• wherein a given layer in the instance of the stack is defined using single-crystal regrowth of the semiconductor layer.

A method for modulating an optical signal, comprising:

• conveying the optical signal in an optical waveguide defined in a semiconductor layer, wherein the semiconductor layer is disposed on a buried-oxide (BOX) layer and the BOX layer is disposed on a substrate;
• and
• applying a bias voltage to a p-n junction in the semiconductor layer, wherein the p-n junction is included in a stack that includes:
• an outer n-type layer having a minimum n-type doping level, an intermediate n-type layer having an intermediate n-type doping level that is greater than the minimum n-type doping level, a junction n-type layer having a maximum n-type doping level that is greater than the intermediate n-type doping level, a junction p-type layer having a maximum p-type doping level, an intermediate p-type layer having an intermediate p-type doping level that is less than the maximum p-type doping level, and an outer p-type layer having a minimum p-type doping level that is less than the intermediate p-type doping level;
• and
• wherein a given layer in the instance of the stack is defined using single-crystal regrowth of the semiconductor layer.