Devices and techniques for integrated optical data communication
Devices and techniques for integrated optical data communication. A method of encoding symbols in an optical signal may include encoding a first symbol by injecting charge carriers, at a first rate, into a semiconductor device, such as a PIN diode. The method may also include encoding a second symbol by injecting charge carriers, at a second rate, into the semiconductor device. The first rate may exceed the second rate. A modulator driver circuit may include a resistive circuit coupled between supply terminal and drive terminals. The modulator driver circuit may also include a control circuit coupled between a data terminal and the resistive circuit. The control circuit may modulate a resistance of the resistive circuit by selectively coupling one or more of a plurality of portions of the resistive circuit to the drive terminal based on data to be optically encoded. In some embodiments, a modulator driver circuit and an optical modulator may be integrated on the same die or stacked (3D integrated) die and connected with through-oxide or through-silicon vias.
1. A method of fabricating an integrated circuit in a manufacturing process, comprising:
in a silicon layer of the manufacturing process, fabricating a body of a transistor of a modulator driver circuit configured to control an optical modulator, the transistor being configured to modulate a resistance between an optical modulator and a supply, wherein the silicon layer is a first layer of the manufacturing process;
in a second layer of the manufacturing process, fabricating a gate of the transistor of the modulator driver circuit;
fabricating an optical waveguide core in the silicon layer of the manufacturing process; and
fabricating a diode in the silicon layer of the manufacturing process, wherein a portion of the optical waveguide core is embedded in a portion of the diode.
2. The method of claim 1 , wherein the manufacturing process is a bulk silicon process.
3. The method of claim 1 , wherein the manufacturing process is a 65 nm process, a 45 nm process, a 32 nm process, or a 28 nm process.
4. The method of claim 1 , wherein the manufacturing process is a silicon-on-insulator (SOI) process.
5. The method of claim 1 , wherein the silicon layer is doped.
6. The method of claim 1 , wherein the second layer of the manufacturing process comprises a poly-silicon layer.
7. The method of claim 1 , further comprising capping the second layer of the manufacturing process with a layer of nickel silicide.
8. The method of claim 1 , wherein the second layer of the manufacturing process has a thickness that is between 65 nm and 200 nm.
9. The method of claim 1 , further comprising fabricating an optical resonator in the silicon layer of the manufacturing process.
10. The method of claim 1 , wherein fabricating the optical waveguide core comprises fabricating at least one waveguide core selected from the group consisting of a rib waveguide core and a strip waveguide core.
11. The method of claim 1 , wherein fabricating the diode comprises fabricating at least one diode selected from the group consisting of a PIN diode and a PN junction diode.