Photon generator

Abstract

The invention provides an apparatus for optical integrated on-chip generation of photon pairs as a building block to create entangled photon states required for quantum information processing. The invention provided a frequency selective optical coupling device which controls the transmission of light by varying the relative dimensions of otherwise symmetrical linear optical waveguides tangential to an annular optical waveguide, thereby controlling the coupling of light between the linear optical waveguides and the annular optical waveguide. Dimensional change of the optical waveguides is achieved by a heated medium in proximity of the optical waveguides and under electronic control.

What is claimed is: 
     
         1 . A frequency selective optical coupling device, comprising:
 an annular optical channel;   a first linear optical channel having a first input and a first output,
 said first linear optical channel being substantially tangential to said annular optical channel at a first point and a second point; 
   a second linear optical channel having a second input and a second output,
 said second linear optical channel being substantially tangential to said annular optical channel at a third point and a fourth point; and 
   a predeterminable relative phase delay between said first and said second linear optical channels,
 so as to cause a variance in an amount of light traversing said first and said second linear optical channels as a function of the frequency of said light. 
   
     
     
         2 . The frequency selective optical coupling device of  claim 1 , wherein said substantial tangentiality permits a coupling of light between said annular optical channel and said linear optical channels at said first, said second, said third and said fourth points. 
     
     
         3 . The frequency selective optical coupling device of  claim 1 , wherein said predeterminable relative phase delay is induced by a relative difference in length between said first linear optical channel and said second linear optical channel. 
     
     
         4 . The frequency selective optical coupling device of  claim 3 , wherein said relative difference in length is induced by thermal expansion. 
     
     
         5 . The frequency selective optical coupling device of  claim 4 , wherein said thermal expansion is induced by a heated medium in proximity of said channels. 
     
     
         6 . A photon generator device, comprising:
 an annular optical channel disposed in a chip;   a first linear optical channel disposed in said chip, said channel having a first input and a first output, said first input and a first output being in common with each other and with an input to said chip;
 said first linear optical channel being substantially tangential to said annular optical channel at a first point and a second point; 
   a second linear optical channel disposed in said chip, said channel having a second input and a second output,
 said second linear optical channel being substantially tangential to said annular optical channel at a third point and a fourth point; 
   a first predeterminable relative phase delay between said first and said second linear optical channels, so as to cause a variance in an amount of light traversing said first and said second linear optical channels as a function of the frequency of said light;   a second predeterminable relative phase delay between said second input and said second output;   a photon detector sampling each of said second input and said second output;   a third output of said chip in common with said second input;   a fourth output of said chip in common with said second output; and   an electronic control subsystem in operative communication with said chip for facilitating said predeterminable relative phase delays and said photon detection.   
     
     
         7 . The photon generator device of  claim 9 , wherein said substantial tangentiality permits a coupling of light between said annular optical channel and said linear optical channels at said first, said second, said third and said fourth points. 
     
     
         8 . The photon generator device of  claim 9 , wherein said first predeterminable relative phase delay is induced by a relative difference in length between said first linear optical channel and said second linear optical channel. 
     
     
         9 . The photon generator device of  claim 9 , wherein said second predeterminable relative phase delay is induced by a relative difference in the length of optical channel from said second input to said third output, and the length of optical channel from said second output to said fourth output. 
     
     
         10 . The photon generator device of  claim 11  or claim  12  wherein said relative difference in length is induced by thermal expansion. 
     
     
         11 . The photon generator device of claim  13 , wherein said thermal expansion is induced by a heated medium in proximity of said optical channels.