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US 7,466,926 B2Granted
Method and apparatus for RZ-DPSK optical signal generation
AssigneeAlcatel-Lucent USA Inc.
InventorsYuan-Hua Kao, Xiang Liu
Life of this patent
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Abstract
An apparatus and method for generating chirp-free return-to-zero differential phase-shift keyed optical signals using a modulator driven by at least one 3-level return-to-zero drive signals.
Claims25
A method of generating a return-to-zero (RZ) differential phase-shift-keyed (DPSK) optical signal comprising the steps of:
- generating a 3-level RZ drive signal;
- and
- driving a modulator with the 3-level RZ drive signal to generate the RZ-DPSK optical signal, wherein the step of generating the 3-level RZ drive signal includes the steps of:
- performing a logic AND operation on a differentially encoded data signal and a clock signal to generate a first 2-level drive signal, wherein the differentially encoded data signal is a binary signal having first and second binary states;
- performing a logic AND operation on an inverse of the differentially encoded data signal and the clock signal to generate a second 2-level drive signal;
- and
- differentially amplifying the first and second 2-level drive signals to generate the 3-level RZ drive signal, wherein each occurrence of a binary state in the differentially encoded data signal is represented in the 3-level RZ drive signal by a positive pulse or a negative pulse relative to a reference level.
4 more elements
A method for generating return-to-zero (RZ) differential phase-shift-keyed (DPSK) optical signals comprising the steps of:
- performing a logic AND operation on a differentially encoded data signal and a clock signal to generate a first 2-level drive signal, wherein the differentially encoded data signal is a binary signal having first and second binary states,
- performing a logic AND operation on an inverse of the differentially encoded data signal and the clock signal to generate a second 2-level drive signal,
- differentially amplifying the first 2-level drive signal with the second 2-level drive signal to generate a first 3-level RZ drive signal;
- differentially amplifying the inverse of the first 2-level RZ drive signals to generate the RZ-DPSK optical signals, wherein, for at least one of the first and second 3-level RZ drive signals each occurrence of a binary state in the differentially encoded data signal is represented in the 3level RZ drive signal by a positive pulse or a negative pulse relative to a reference level.
1 more element
A method of generating a return-to-zero (RZ) M-ary differential-phase amplitude-shift-keyed (DP-ASK) optical signal, comprising the steps of:
- generating an M-level RZ drive signal, wherein M is an integer greater than three;
- and
- driving a modulator with the M-level RZ drive signal, wherein the modulator modulates both intensity and phase of an optical beam to generate the RZ M-ary DP-ASK optical signal, wherein the step of generating the M-level RZ drive signal includes the steps of:
- performing a logic AND operation on a plurality of differentially encoded data signals and a clock signal to generate a plurality of first 2-level drive signals,
- performing a logic AND operation on an inverse of the plurality of differentially encoded data signals and the clock signal to generate a plurality of second 2-level drive signals,
- power combining each first 2-level drive signal with an inverse of the corresponding second 2-level drive signal to generate each of a plurality of 3-level RZ drive signals;
- and
- power combining the plurality of 3-level RZ drive signals to generate the M-level RZ drive signal.
5 more elements
An apparatus for generating an RZ-DPSK optical signal, comprising:
- drive circuitry adapted to generate at least one 3-level RZ drive signal;
- and
- a modulator coupled to the drive circuitry such that the at least one 3-level RZ drive signal drives the modulator to generate the RZ-DPSK optical signal, wherein the drive circuitry comprises:
- a first logic AND gate adapted to perform a logic AND operation on a differentially encoded data signal and a clock signal to generate a first 2-level drive signal, wherein the differentially encoded data signal is a binary signal having first and second binary states;
- a second logic AND gate adapted to perform a logic AND operation on an inverse of the differentially encoded data signal and the clock signal to generate a second 2-level drive signal, and
- a differential amplifier adapted to differentially amplify the first and second 2-level drive signals to generate the 3-level RZ drive signal, wherein each occurrence of a binary state in the differentially encoded data signal is represented in the 3-level RZ drive signal by a positive pulse or a negative pulse relative to a reference level.
3 more elements
An apparatus for generating RZ-DPSK optical signals comprising:
- a first differential amplifier adapted to receive a differentially encoded data signal and a clock signal and generate a first 2-level drive signal, wherein the differentially encoded data signal is a binary signal having first and second binary states;
- a second differential amplifier adapted to receive an inverse of the differentially encoded data signal and the clock signal and generate a second 2-level drive signal;
- an inverter for inverting the second 2-level drive signal;
- a third differential amplifier adapted to receive the first 2-level drive signal and the inverted second 2-level drive signal to generate a 3-level RZ drive signal, wherein each occurrence of a binary state in the differentially encoded data signal is represented in the 3-level RZ drive signal by a positive pulse or a negative pulse relative to a reference level;
- and
- a modulator coupled to the third differential amplifier such that the 3-level RZ drive signal drives the modulator to generate RZ-DPSK optical signals.
3 more elements
An apparatus for generating a return-to-zero (RZ) M-ary differential-phase-amplitude-shift-keyed (M-ary DP-ASK) optical signal, comprising:
- means for generating an M-level RZ drive signal and for driving a single modulator with the drive signal, wherein M is an integer greater than three and the modulator is adapted to modulate both intensity and phase of an optical beam to generate the RZ M-ary DP-ASK optical signal, wherein the means for generating comprises:
- a first plurality of logic AND gates, each adapted to perform a logic AND operation on a respective signal of a plurality of differentially encoded data signals and a clock signal to generate a plurality of first 2-level drive signals,
- a second plurality of logic AND gates, each adapted to perform a logic AND operation on an inverse of the plurality of differentially encoded data signals and the clock signal to generate a plurality of second 2-level drive signals,
- a plurality of power combiners, each adapted to power combine a corresponding one of the first 2-level drive signals with an inverse of the corresponding second 2-level drive signal to generate a corresponding one of a plurality of 3-level RZ drive signals;
- and
- an additional power combiner adapted to power combine the plurality of 3-level RZ drive signals to generate the M-level RZ drive signal.
3 more elements
A method of generating a return-to-zero (RZ) M-ary differential-phase amplitude-shift-keyed (DP-ASK) optical signal, comprising the steps of:
- generating a multi-level RZ drive signal;
- and
- driving a modulator with the drive signal to generate the RZ M-ary DP-ASK optical signal, wherein the step of generating the multi-level RZ drive signal further includes the steps of:
- performing a logic AND operation on a plurality of differentially encoded data signals and a clock signal to generate a plurality of first 2-level drive signals,
- performing a logic AND operation on each of an inverse of the plurality of differentially encoded data signals, and the clock signal to generate a plurality of respective second 2-level drive signal,
- power combining each of the plurality of first 2-level drive signals with a respective inverse of the plurality of respective second 2-level drive signals to generate a plurality of 3-level RZ drive signals;
- and
- power combining the plurality of 3-level RZ drive signals to generate the multi-level RZ drive signal.
5 more elements
Dependencies are inferred from the claim text.