RZ Optical Signal Generation Using XOR Logic Gate
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional RZ-DQPSK modulation systems require a second Mach-Zehnder modulator for RZ pulse carving, increasing manufacturing costs and decreasing operating efficiency.
Innovation Solution
A modulation system that generates a return-to-zero (RZ) electrical drive signal using a single high-speed logic gate, comprising a logic XOR gate and a differential amplifier to drive a Mach-Zehnder modulator, eliminating the need for a second modulator.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a second Mach-Zehnder modulator is used for RZ pulse carving, then RZ optical data signal generation is achieved, but manufacturing cost increases and operating efficiency decreases
Solution Approach 1:
The patent extracts the RZ pulse carving function from a separate second MZ modulator and integrates it into the drive circuitry of the first MZ modulator. By generating an RZ electrical drive signal through logic operations (AND gate) on the NRZ electrical data signal and electrical clock signal, the system eliminates the need for a second modulator while maintaining RZ optical data signal generation capability.
Solution Approach 2:
The patent merges the RZ pulse carving function with the existing MZ modulator drive circuit. The drive circuit is modified to include logic gates that generate RZ electrical drive signals, combining the modulation and RZ pulse generation functions into a single integrated system, thereby reducing device complexity and manufacturing cost.
2Reliability
If two high-speed logic gates are used to generate RZ electrical drive signal, then RZ optical data signal is generated, but device complexity increases
Solution Approach 1:
The patent extracts the essential RZ pulse generation logic and implements it using a simplified logic circuit with only one AND gate. This gate operates on the NRZ electrical data signal and electrical clock signal to generate the RZ electrical drive signal, reducing the logic gate count from two to one while maintaining signal generation capability.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Simplifies the generation of RZ optical data signals, reducing manufacturing costs and improving operating efficiency by using a single high-speed logic gate to produce the RZ electrical drive signal.
Implementation Method 1
The MZ modulators 112 of the first DPMZ modulator 110 are driven with non-return-to-zero (NRZ) electrical data signals 120 to generate NRZ optical data signals 130 having a relative phase shift of π/2, which are components of an NRZ-DQPSK optical data signal 131, by phase-modulating optical carrier signals 132
Implementation Method 2
a differential amplifier, electrically connected to the logic XOR gate and to the MZ modulator, for receiving the electrical intermediate signal and an inverse of the NRZ electrical data signal, and for differentially amplifying the electrical intermediate signal and the inverse of the NRZ electrical data signal to generate the RZ electrical drive signal
Data Source
AI summary
A modulation system and a method for generating a return-to-zero (RZ) optical data signal are provided. The modulation system comprises a Mach-Zehnder (MZ) modulator and a drive circuit, which includes a logic XOR gate and a differential amplifier. The logic XOR gate applies a logic XOR operation to a non-return-to-zero (NRZ) electrical data signal and an inverse of an electrical clock signal to generate an electrical intermediate signal. The differential amplifier differentially amplifies the electrical intermediate signal and an inverse of the NRZ electrical data signal to generate an RZ electrical drive signal. The drive circuit drives the MZ modulator with the RZ electrical drive signal to generate the RZ optical data signal.