Method and apparatus for optically modulating light through the back side of an integrated circuit die along the side walls of junctions

A method of modulating an optical beam, comprising:

• directing an optical beam through a back side of a semiconductor substrate of an integrated circuit die having a front side and the back side, the optical beam directed through a first charged region extending from a side wall of a first doped region disposed within the semiconductor substrate, the optical beam directed through a path through the first charged region along the side wall of the first doped region;
• deflecting the optical beam back through the path through the first charged region back out the back side;
• and
• modulating a charge density of the first charged region in response to a signal of the integrated circuit die.

An optical modulator, comprising:

• a semiconductor substrate of an integrated circuit die, the semiconductor substrate having including a front side and a back side;
• a doped region disposed in the semiconductor substrate;
• a charged region proximate to a side wall of the doped region at a junction between the doped region and the semiconductor substrate, a charge density of the charged region to be modulated in response to a signal of the integrated circuit die;
• and
• a deflector proximate to the doped region such that an optical beam is to be directed through the back side of the semiconductor substrate through the charged region along the side wall of the doped region to the deflector, the deflector to deflect the optical beam back through the charged region along the side wall of the doped region back through the back side of the semiconductor substrate.