Method and system for a low-voltage integrated silicon high-speed modulator
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.
1. A method for communication, the method comprising:
in an optical modulator comprising an optical waveguide and an optical phase shifter, the optical phase shifter comprising a p-n junction with a horizontal section and a vertical section, wherein;
an n-doped region is in a slab waveguide portion and in a rib waveguide portion of the phase shifter and a p-doped region is in the slab waveguide portion but not in the rib waveguide portion;
a p+ doped region is adjacent to the p-doped region and extends from the p-doped region to a p++ region;
a n+ doped region is adjacent to the p-doped region and extends from the n-doped region to a n++ region; and
a top surface of the p++ region and a top surface of the n++ region are above a top surface of the slab waveguide portion of the phase shifter:
communicating an optical signal to the optical waveguide; and
modulating a phase of the optical signal in the waveguide utilizing the optical phase shifter.
2. The method according to claim 1 , comprising reverse-biasing the p-n junction of the phase shifter.
3. The method according to claim 1 , comprising applying a modulating signal to the phase shifter.
4. The method according to claim 1 , wherein the horizontal and vertical sections of the p-n junction form an “L” shape.
5. The method according to claim 1 , wherein the p-n junction comprises three rectangular sections, a first section being a p-type semiconductor layer, a second section being a portion of an n-type semiconductor layer coplanar with the first section, and a third section being another portion of the n-type semiconductor layer but formed above the first and second sections.
6. The method according to claim 5 , comprising reverse biasing the p-n junction such that a depletion width of the p-n junction extends across most but not all of the third section.
7. The method according to claim 1 , wherein the modulator is integrated in silicon.
8. The method according to claim 1 , wherein the horizontal section of the p-n junction is at an intersection of the rib waveguide portion and the slab waveguide portion and the vertical section of the p-n junction is only in the slab waveguide portion.
9. The method according to claim 1 , wherein the modulator is integrated in a CMOS chip.
10. The method according to claim 1 , wherein the p-n junction is formed by ion implantation.
11. A system for communication, the system comprising:
an optical modulator comprising an optical waveguide and a phase shifter, wherein the optical phase shifter comprises a p-n junction with a horizontal section and a vertical section, wherein:
an n-doped region is in a slab waveguide portion and in a rib waveguide portion of the phase shifter and a p-doped region is in the slab waveguide portion but not in the rib waveguide portion;
a p+ doped region is adjacent to the p-doped region and extends from the p-doped region to a p++ region;
a n+ doped region is adjacent to the p-doped region and extends from the n-doped region to a n++ region; and
a top surface of the p++ region and a top surface of the n++ region are above a top surface of the slab waveguide portion of the phase shifter,
and wherein the optical modulator is operable to:
receive an optical signal in the optical waveguide; and
modulate a phase of the optical signal in the waveguide utilizing the optical phase shifter.
12. The system according to claim 11 , wherein said phase shifter is reverse-biased.
13. The system according to claim 11 , wherein said modulator is operable to modulate a received signal when a modulating signal is applied to the phase shifter.
14. The system according to claim 11 , wherein the horizontal and vertical sections of the p-n junction form an “L” shape.
15. The system according to claim 11 , wherein the p-n junction comprises three rectangular sections, a first section being a p-type semiconductor layer, a second section being a portion of an n-type semiconductor layer coplanar with the first section, and a third section being another portion of the n-type semiconductor layer but formed above the first and second sections.
16. The system according to claim 15 , wherein a reverse bias is applied to the p-n junction such that a depletion width of the p-n junction extends across most but not all of the third section.
17. The system according to claim 11 , wherein the modulator is integrated in silicon.
18. The system according to claim 11 , wherein the horizontal section of the p-n junction is at an intersection of the rib waveguide portion and the slab waveguide portion and the vertical section of the p-n junction is only in the slab waveguide portion.
19. The system according to claim 11 , wherein the p-n junction is formed by ion implantation.
20. A system for communication, the system comprising:
an optical modulator in a silicon photonic transceiver, said optical modulator comprising:
an optical waveguide;
an optical phase shifter comprising a rib waveguide section on top of a slab waveguide section and a p-n junction with a horizontal section and a vertical section, wherein the horizontal section is formed by a portion of an n-doped layer formed on a p-doped layer where the p-doped layer is in the slab waveguide section but not in the rib waveguide portion, wherein:
the vertical portion is formed by another portion of the n-doped layer that is in the same plane as the p-doped layer;
a p+ doped layer is adjacent to the p-doped layer and extends from the p-doped layer to a p++ region;
a n+ doped region is adjacent to the p-doped region and extends from the n-doped region to a n++ region; and
a top surface of the p++ region and a top surface of the n++ region are above a top surface of the slab waveguide section of the phase shifter, and wherein the optical modulator is operable to:
receive an optical signal in the optical waveguide; and
modulate a phase of the optical signal in the waveguide utilizing the optical phase shifter.