Distributed amplifier optical modulators
View Patent ↗High speed optical modulators can be made of k modulators connected in series disposed on one of a variety of semiconductor substrates. An electrical signal propagating in a microwave transmission line is tapped off of the transmission line at regular intervals and is amplified by k distributed amplifiers. Each of the outputs of the k distributed amplifiers is connected to a respective one of the k modulators. Distributed amplifier modulators can have much higher modulating speeds than a comparable lumped element modulator, due to the lower capacitance of each of the k modulators. Distributed amplifier modulators can have much higher modulating speeds than a comparable traveling wave modulator, due to the impedance matching provided by the distributed amplifiers.
1. An optoelectronic device comprising:
a waveguide structure including a plurality of optical modulator elements each having an optical property that is adjustable upon application of an electrical signal so as to modulate light guided in said waveguide structure; and
a plurality of amplifiers, each amplifier separately electrically coupled to a respective one of said optical modulators to apply electrical signals thereto;
wherein at least one of the plurality of amplifiers comprises a push-pull driver circuit.
2. The optoelectronic device of claim 1 , wherein the waveguide structure comprises a Mach-Zehnder interferometer.
3. The optoelectronic device of claim 1 , further comprising a multi-tap delay line comprised of a plurality of electrical delay elements coupled in series, the multi-tap delay line having an input port and a plurality of output ports, wherein each one of the plurality of output ports comprises the output of a respective one of the plurality of delay elements, and each one of the plurality of output ports is coupled to a respective input port of the plurality of amplifiers.
4. The optoelectronic device of claim 3 , wherein an electrical propagation velocity of the electrical signal in the plurality of delay elements is substantially equal to an optical propagation velocity of light in the plurality of optical modulator elements.
5. The optoelectronic device of claim 1 , further comprising a microwave transmission line.
6. The optoelectronic device of claim 5 , wherein the microwave transmission line is comprised of a plurality of sections that each provide electrical delay, said sections coupled in series.
7. The optoelectronic device of claim 6 , wherein an electrical propagation velocity of the electrical signal in the plurality of sections is substantially equal to an optical propagation velocity of light in the plurality of optical modulator elements.
8. The optoelectronic device of claim 1 , wherein the optoelectronic device is disposed on a substrate selected from a group consisting of: monocrystalline silicon, a silicon on insulator substrate, sapphire, and a substrate comprising an air filled cavity.
9. The optoelectronic device of claim 1 , wherein each of the plurality of optical modulator elements is selected from a group consisting of: an electroabsorptive modulator, a phase modulator, and a PN modulator.
10. The optoelectronic device of claim 1 , wherein the waveguide structure comprises two arms and each arm comprises a plurality of optical modulator elements.
11. The optoelectronic device of claim 10 , wherein said plurality of amplifiers includes amplifiers separately electrically coupled to respective ones of said optical modulator elements in one of said arms.