Electro-optic modulation
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. An electro-optic modulator comprising:
a ring waveguide supported by a substrate; and
a p-i-n junction embedded in the ring waveguide having highly doped p and n regions at least partially separated from a resonating mode of the ring waveguide.
2. The electro-optic modulator of claim 1 wherein the p-i-n junction includes highly doped regions on both an inside and outside of the ring waveguide.
3. The electro-optic modulator of claim 1 wherein the ring waveguide comprises a high aspect ratio rib of silicon.
4. The electro-optic modulator of claim 3 wherein the rib of silicon is supported by a slab of silicon, and wherein the highly doped regions are formed in the slab.
5. The electro-optic modulator of claim 1 and further comprising an input port waveguide coupled to a first side of the ring waveguide.
6. The electro-optic modulator of claim 5 and further comprising a second waveguide coupled to a second side of the ring waveguide.
7. The electro-optic modulator of claim 1 wherein the p-i-n junction comprises highly doped n regions on both an inside and outside of the ring waveguide.
8. An electro-optic modulator comprising:
a ring waveguide supported by a substrate; and
a MOS diode integrated with the ring waveguide to cause changes in a refractive index of the ring waveguide.
9. The electro-optic modulator of claim 8 wherein the MOS diode comprises:
highly doped regions on both an inside and outside of the ring waveguide; and
a gate separated from a top of the ring waveguide by a layer of insulation.
10. The electro-optic modulator of claim 8 wherein the ring waveguide comprises a high aspect ratio rib of silicon.
11. The electro-optic modulator of claim 10 wherein the rib of silicon is supported by a slab of silicon, and wherein the highly doped regions are formed in the slab.
12. The electro-optic modulator of claim 8 and further comprising an input port waveguide coupled to a first side of the ring waveguide.
13. The electro-optic modulator of claim 12 and further comprising a second waveguide coupled to a second side of the ring waveguide.
14. The electro-optic modulator of claim 8 wherein the MOS diode comprises highly doped n regions on both an inside and outside of the ring waveguide.