Electro-optic modulation

Abstract

A silicon electro-optic waveguide modulator is formed using a metal-oxide-semiconductor (MOS) configuration. Various embodiments are described using different modes of operation of the MOS diode and gate oxide thicknesses. In one example, a high-speed submicron waveguide active device is formed using silicon-on-insulator. A micro-ring resonator intensity-modulator exhibits switching times on the order of tens of pS with modulation depth of 73% with a bias voltage of 5 volts.

1 . A method comprising:
 providing light to a waveguide optically coupled to an optical resonator;   modulating the light in the waveguide by varying the optical coupling of the optical resonator to the waveguide.   
     
     
         2 . The method of the  claim 1  wherein the optical coupling is varied by changing a free carrier concentration in the optical resonator to vary the refractive index of the optical resonator. 
     
     
         3 . The method of  claim 1  wherein the optical resonator is a ring resonator. 
     
     
         4 . The method of  claim 1  wherein the optical resonator is a Fabry-Perot resonator. 
     
     
         5 . The method of  claim 1  wherein the optical resonator is an optical cavity. 
     
     
         6 . The method of  claim 1  and further comprising providing a p doped region and an n doped region adjacent to the optical resonator. 
     
     
         7 . The method of  claim 6  wherein the doped regions are heavily doped. 
     
     
         8 . The method of  claim 7  wherein the heavily doped regions form a p-i-n diode about the optical resonator. 
     
     
         9 . The method of  claim 1  wherein the free carrier concentration is changed by at least one of injection, accumulation, depletion and inversion of carriers. 
     
     
         10 . The method of  claim 2  wherein the carrier concentration is changed by a p-i-n diode. 
     
     
         11 . The method of  claim 2  wherein the carrier concentration is changed by metal-oxide-semiconductor field-effect-transistor. 
     
     
         12 . A method comprising:
 providing light to a optical ring resonator;   modulating the light in the optical ring resonator by changing its refractive index.   
     
     
         13 . The method of  claim 12  wherein the refractive index is changed by varying a free carrier concentration in the optical ring resonator. 
     
     
         14 . The method of  claim 12  where the light is provided to the optical ring resonator by an optically coupled waveguide. 
     
     
         15 . The method of  claim 12  and further comprising providing a p doped region and an n doped region adjacent to the optical ring resonator. 
     
     
         16 . The method of  claim 15  wherein the doped regions are heavily doped. 
     
     
         17 . The method of  claim 16  wherein the heavily doped regions form a p-i-n diode about the optical ring resonator. 
     
     
         18 . The method of  claim 12  wherein the free carrier concentration is changed by at least one of injection, accumulation, depletion and inversion of carriers. 
     
     
         19 . The method of  claim 18  wherein the carrier concentration is changed by metal-oxide-semiconductor field-effect-transistor about the optical ring resonator. 
     
     
         20 . A method comprising:
 providing light to a waveguide;   modulating the light in the waveguide by changing the refractive index of an optical resonator coupled to the waveguide.   
     
     
         21 . The method of  claim 20  wherein the refractive index is changed by changing the free carrier concentration in the optical resonator. 
     
     
         22 . The method of  claim 21  wherein varying the refractive index changes optical coupling of the optical waveguide to the waveguide.