Single-electrode push-pull configuration for semiconductor PIN modulators

A push-pull semiconductor PIN modulator comprising:

• a substrate;
• a first PIN device formed on the substrate and including an N-type layer, an intrinsic layer and a P-type layer;
• a second PIN device formed on the substrate and including an N-type layer, an intrinsic layer and a P-type layer;
• a first electrode formed on the substrate, said first electrode being electrically coupled to the N-type layer of the first PIN device and the P-type layer of the second PIN device;
• and
• a biasing system, said biasing system providing an RF signal to the first electrode that causes the index of refraction of the intrinsic layer of the first PIN device to change in one direction and the index of refraction of the intrinsic layer of the second PIN device to change in an opposite direction to provide a push-pull effect.

A method of modulating an optical signal with an RF signal, said method comprising:

• electrically coupling a first electrode to a P-type layer of a first PIN device and an N-type layer of a second PIN device;
• electrically coupling a second electrode to an N-type layer of the first PIN device;
• electrically coupling a third electrode to a P-type layer of the second PIN device;
• propagating the optical signal down a Mach-Zehnder interferometer so that the optical signal passes through an intrinsic layer of the first PIN device and an intrinsic layer of the second PIN device;
• and
• applying an RF signal to the first, second and third electrodes so that the index of refraction of the intrinsic layer of the first PIN device changes in one direction and the index of refraction of the intrinsic layer of the second PIN device changes in an opposite direction.