Method And System For A Low-Voltage Integrated Silicon High-Speed Modulator

Abstract

Methods and systems for a low-voltage integrated silicon high-speed modulator may include an optical modulator comprising first and second optical waveguides and two optical phase shifters, where each of the two optical phase shifters may comprise a p-n junction with a horizontal section and a vertical section and an optical signal is communicated to the first optical waveguide. A portion of the optical signal may then be coupled to the second optical waveguide. A phase of at least one optical signal in the waveguides may be modulated utilizing the optical phase shifters. A portion of the phase modulated optical signals may be coupled between the two waveguides, thereby generating two output signals from the modulator. A modulating signal may be applied to the phase shifters which may include a reverse bias.

What is claimed is: 
     
         1 . A waveguide, comprising:
 a slab portion including a p-doped region and a first n-doped region that abut to define a first PN junction in a first plane and including a first surface in a second plane perpendicular to the first plane; and   a rib portion including a second n-doped region that projects perpendicularly from the first plane from the p-doped region and the first n-doped region and defines a second PN junction in the second plane.   
     
     
         2 . The waveguide of  claim 1 , further comprising:
 a p+ doped region extending from the p-doped region in a first direction perpendicular to the first plane and including a first portion that projects from the first surface to a third plane parallel to the second plane; and   an n+ doped region extending from the first n-doped region in a second direction opposite to the first direction and including a second portion that projects from the first surface to the third plane.   
     
     
         3 . The waveguide of  claim 2 , further comprising:
 a p++ doped region extending from the first portion of the p+ doped region; and   an n++ doped region extending from the second portion of the n+ doped region.   
     
     
         4 . The waveguide of  claim 3 , further comprising:
 a first electrical contact connected to the p++ doped region; and   a second electrical contact connected to the n++ doped region.   
     
     
         5 . The waveguide of  claim 3 , wherein:
 the first n-doped region and the second n-doped region are doped at an equal concentration;   the n+ doped region is doped at a higher concentration than the first n-doped region;   the n++ doped region is doped at a higher concentration than the n+ doped region;   the p+ doped region is doped at a higher concentration than the p-doped region; and   the p++ doped region is doped at a higher concentration than the p+ doped region.   
     
     
         6 . The waveguide of  claim 1 , wherein the second plane is separated from a third plane that is parallel to the second plane by a junction offset, wherein the third plane bisects the rib portion. 
     
     
         7 . The waveguide of  claim 6 , wherein the p-doped region contacts the rib portion on both sides of the third plane. 
     
     
         8 . A waveguide, comprising:
 a first doped portion having a first side, a second side, and a third side;   a second doped portion, having a fourth side;   a third doped portion, having a fifth side, and sixth side, and a seventh side;   wherein the fourth side of the second doped portion abuts the third side of the first doped portion and the seventh side of the third doped portion and forms a first PN junction with a region of the seventh side of the third doped portion that the fourth side of the second doped portion abuts to;   wherein the second side of the first doped portion abuts the sixth side of the third doped portion and forms a second PN junction; and   wherein the first side of the first doped portion and the fifth side of the third doped portion are coplanar; and   wherein the third side of the first doped portion, the fourth side of the second doped portion, and the seventh side of the third doped portion are coplanar.   
     
     
         9 . The waveguide of  claim 8 , wherein the first doped portion and the second doped portion are n doped, and wherein the third doped portion is p doped. 
     
     
         10 . The waveguide of  claim 8 , wherein the first doped portion and the second doped portion are p doped, and wherein the third doped portion is n doped. 
     
     
         11 . The waveguide of  claim 8 , wherein the second doped portion is bisected by a first plane parallel to the second PN junction, wherein the second PN junction is located in a second plane offset from the first plane by a junction offset. 
     
     
         12 . The waveguide of  claim 11 , wherein the third doped portion extends past the first plane to contact more of the fourth side of the second doped portion than the first doped portion contacts. 
     
     
         13 . The waveguide of  claim 8 , further comprising:
 a fourth doped portion, doped at a higher concentration than the first doped portion, connected to the first doped portion opposite to the second PN junction; and   a fifth doped portion, doped at a higher concentration than the third doped portion, connected to the second doped portion opposite to the second PN junction.   
     
     
         14 . A waveguide, comprising:
 a slab portion including an n-doped region and a first p-doped region that abut to define a first PN junction in a first plane and including a first surface in a second plane perpendicular to the first plane; and   a rib portion including a second p-doped region that projects perpendicularly from the first plane from the n-doped region and the first p-doped region and defines a second PN junction in the second plane.   
     
     
         15 . The waveguide of  claim 14 , further comprising:
 a p+ doped region extending from the first p-doped region in a first direction perpendicular to the first plane and including a first portion that projects from the first surface to a third plane parallel to the second plane; and   an n+ doped region extending from the n-doped region in a second direction opposite to the first direction and including a second portion that projects from the first surface to the third plane.   
     
     
         16 . The waveguide of  claim 15 , further comprising:
 a p++ doped region extending from the first portion of the p+ doped region; and   an n++ doped region extending from the second portion of the n+ doped region.   
     
     
         17 . The waveguide of  claim 16 , further comprising:
 a first electrical contact connected to the p++ doped region; and   a second electrical contact connected to the n++ doped region.   
     
     
         18 . The waveguide of  claim 16 , wherein:
 the first p-doped region and the second p-doped region are doped at an equal concentration;   the n+ doped region is doped at a higher concentration than the n-doped region;   the n++ doped region is doped at a higher concentration than the n+ doped region;   the p+ doped region is doped at a higher concentration than the first p-doped region; and   the p++ doped region is doped at a higher concentration than the p+ doped region.   
     
     
         19 . The waveguide of  claim 14 , wherein the second plane is separated from a third plane that is parallel to the second plane by a junction offset, wherein the third plane bisects the rib portion. 
     
     
         20 . The waveguide of  claim 19 , wherein the n-doped region contacts the rib portion on both sides of the third plane.