Photonic crystal band-shifting device for dynamic control of light transmission

An apparatus for dynamic control of light transmission comprising:

• a photonic crystal waveguide comprising:
• a substrate;
• a slab disposed on the substrate;
• a core in the slab having an input side on a first end of the waveguide and an output side on a second end of the waveguide;
• two electrically conductive pads disposed onto the slab and adjacent to a portion of the core;
• a first region of the core between the electrically conductive pads;
• a second region of the core between the input side of the waveguide and the first region of the core, wherein the second region comprises a gradually increasing group index;
• a third region of the core between the first region of the core and the output side of the waveguide, wherein the third region comprises a gradually decreasing group index;
• a first evanescent field optical mode converter coupled to the second region of the core;
• and
• a second evanescent field optical mode converter coupled to the third region of the core.

A method for applying dynamic control to a signal comprising:

• transmitting the signal into a first transition region, wherein the first transition region comprises a first photonic crystal waveguide with a gradually increasing group index;
• transmitting the signal from the first transition region into a core region that can be dynamically tuned by external voltage or current;
• and
• transmitting the signal from the core region into a second transition region, wherein the second transition region comprises a second photonic crystal waveguide with a gradually decreasing group index.