Distributed traveling-wave Mach-Zehnder modulator driver
A distributed traveling-wave Mach-Zehnder modulator driver having a plurality of modulation stages that operate cooperatively (in-phase) to provide a signal suitable for use in a 100 Gb/s optical fiber transmitter at power levels that are compatible with conventional semiconductor devices and conventional semiconductor processing is described.
1. A distributed traveling wave modulator, comprising:
a differential optical input for receiving an optical input carrier signal and a differential optical output for providing a modulated optical carrier signal;
a plurality of optical phase-shifters connected in series as sequential modulators between said differential optical input and said differential optical output;
a plurality of driver amplifier stages, each including a respective differential driver amplifier input, a differential driver amplifier output, and a differential signal output connected to a respective one of said sequential modulators;
a plurality of delay/relay stages, each including a respective differential delay/relay input and a differential delay/relay output, each of said delay/relay stages connected between two driver amplifier stages;
a differential electrical data input connected to the differential driver amplifier input of a first of said plurality of driver amplifier stages; and
a plurality of DC bias elements, each DC bias element configured to individually control one of said plurality of delay/relay stages;
wherein each DC bias element is capable of controlling an on state and an off state of a respective delay/relay stage for shutting down redundant delay/relay stages.
2. The modulator according to claim 1 , wherein each DC bias element is capable of controlling an on state and an off state of a respective driver amplifier stage for shutting down redundant driver amplifier stages.
3. The modulator according to claim 1 , wherein each driver amplifier stage includes only a single type of transistor to enable high-speed operation.
4. The modulator according to claim 1 , wherein each of the plurality of sequential optical phase shifters comprises a fixed optical length.
5. The modulator according to claim 1 , wherein each of the driver amplifier stages includes a pre-amplifier stage.
6. The modulator according to claim 1 , wherein each output of each driver amplifier stage is configured to be open-collector for driving both 25Ω and 50Ω impedance modulators.
7. The modulator according to claim 1 , wherein the plurality of optical phase shifters comprises four sequential Mach-Zehnder modulator pairs.
8. A distributed traveling wave modulator, comprising:
a differential optical input for receiving an optical input carrier signal and a differential optical output for providing a modulated optical carrier signal;
a plurality of optical phase-shifters connected in series as sequential modulators between said differential optical input and said differential optical output;
a plurality of driver amplifier stages, each including a respective differential driver amplifier input, a differential driver amplifier output, and a differential signal output connected to a respective one of said sequential modulators;
a plurality of delay/relay stages, each including a respective differential delay/relay input and a differential delay/relay output, each of said delay/relay stages connected between two driver amplifier stages; and
a differential electrical data input connected to the differential driver amplifier input of a first of said plurality of driver amplifier stages;
a plurality of DC bias elements, each DC bias element configured to individually control biasing voltages of said plurality of delay/relay stages and said plurality of driver amplifier stages for independently controlling each delay/relay stage and each driver amplifier stage separate from other delay/relay stages and other driver amplifier stages, respectively.
9. The modulator according to claim 8 , wherein each DC bias element capable of controlling an on state and an off state of a respective driver amplifier stage for shutting down redundant driver amplifier stages and/or delay/relay stages.
10. The modulator according to claim 8 , wherein each driver amplifier stage includes only a single type of transistor to enable high-speed operation.
11. The modulator according to claim 8 , wherein each of the plurality of sequential optical phase shifters comprises a fixed optical length.
12. The modulator according to claim 8 , wherein each of the driver amplifier stages includes a pre-amplifier stage.
13. The modulator according to claim 8 , wherein each output of each driver amplifier stage is configured to be open-collector for driving both 25Ω and 50Ω impedance modulators.
14. The modulator according to claim 8 , wherein said plurality of sequential modulators comprise four sequential Mach-Zehnder modulator pairs.