Method and system for a low-voltage integrated silicon high-speed modulator
View Patent ↗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 first and second optical waveguides and two optical phase shifters, each of the two optical phase shifters comprising a p-n junction with a horizontal section and a vertical section, wherein in each of the two optical phase shifters, a first of a p-doped region and an n-doped region is in a slab waveguide portion and in a rib waveguide portion of the phase shifters and a second of the p-doped region and n-doped region is only in the slab waveguide portion, and wherein in each of the two optical phase shifters, p+ and p++ regions and n+ and n++ regions extend above a top surface of the waveguide portion of the phase shifters such that the p++ and n++ regions are at a same height as a top of the rib waveguide portion:
communicating an optical signal to the first optical waveguide, wherein a portion of the optical signal is coupled to the second optical waveguide;
modulating a phase of at least one optical signal in the first and second waveguides utilizing the optical phase shifters; and
coupling a portion of the phase modulated optical signals between the two waveguides, thereby generating output signals from both output waveguides of the modulator.
2. The method according to claim 1 , comprising reverse-biasing the p-n junction of the phase shifters.
3. The method according to claim 1 , comprising applying a modulating signal to the phase shifters.
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 first and second optical waveguides and two optical phase shifters, wherein each of the two optical phase shifters comprises a p-n junction with a horizontal section and a vertical section, wherein in each of the two optical phase shifters, a first of a p-doped region and an n-doped region is in a slab waveguide portion and in a rib waveguide portion of the phase shifters and a second of the p-doped region and n-doped region is only in the slab waveguide portion, wherein in each of the two optical phase shifters, p+ and p++ regions and n+ and n++ regions extend above a top surface of the waveguide portion of the phase shifters such that the p++ and n++ regions are at a same height as a top of the rib waveguide portion, and wherein the optical modulator is operable to:
receive an optical signal in the first optical waveguide,
couple a portion of the optical signal from the first waveguide to the second optical waveguide;
modulate a phase of at least one optical signal in the first and second waveguides utilizing the optical phase shifters; and
couple a portion of the phase modulated optical signals between the first and second waveguides, thereby generating output signals into both output waveguides of the modulator.
12. The system according to claim 11 , wherein said phase shifters are 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 shifters.
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 11 , 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:
first and second optical waveguides;
first and second optical phase shifters, each of the two optical phase shifters 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 only in the slab waveguide section, and the vertical portion is formed by another portion of the n-doped layer that is in the same plane as the p-doped layer, and wherein in each of the first and second optical phase shifters, p+ and p++ regions and n+ and n++ regions extend above a top surface of the slab waveguide section of the phase shifters such that the p++ and n++ regions are at a same height as a top of the rib waveguide section, and wherein the optical modulator is operable to:
receive an optical signal in the first optical waveguide,
couple a portion of the optical signal from the first waveguide to the second optical waveguide;
modulate a phase of at least one optical signal in the first and second waveguides utilizing the optical phase shifters; and
couple a portion of the phase modulated optical signals between the first and second optical waveguides, thereby generating output signals into both output waveguides of the modulator.