Mach-Zehnder Interferometer Optical Transmitter for Multilevel Signals
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Solution Overview
Problem
Current optical transmitter configurations face limitations in increasing the speed of data transmission due to the bottleneck of operation speed in digital signal processors (DSP) and electric circuits, particularly when generating high-speed multilevel optical signals.
Innovation Solution
The optical transmitter employs a Mach-Zehnder interferometer with M×N phase-shift elements, where each symbol carries M bits, and uses time-division multiplexing to generate high-speed optical signals by distributing M×N binary electric signals across N electrode groups, allowing for equal bit rates and phase shifts, thereby reducing the power consumption and increasing transmission speed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single electrode is used to generate multilevel optical signals, then the device complexity is reduced, but the operation speed is limited by the bottleneck of DSP and electric circuits
Solution Approach 1:
The single electrode is divided into multiple segments (first electrode segment and second electrode segment), each capable of independent phase modulation. This segmentation allows parallel processing of multiple data streams, thereby increasing transmission speed while maintaining manageable device complexity through modular electrode structure.
Solution Approach 2:
The patent introduces a temporal dimension by assigning different time slots to different electrode segments for modulating different data streams. This time-division multiplexing approach enables multiple data streams to be transmitted simultaneously through the same physical electrode structure, effectively increasing transmission speed without proportionally increasing device complexity.
2Speed
If multiple electrodes are used to increase transmission speed, then the operation speed is improved, but the power consumption increases
Solution Approach 1:
The patent employs time-division multiplexing where different electrode segments are activated in periodic time slots rather than continuously. Each electrode segment modulates different data streams at different time intervals, reducing the overall power consumption compared to continuous operation of all electrodes, while still achieving high transmission speed through parallel data stream processing.
3Reliability
If the amplitude of electric signal is increased to obtain sufficient optical amplitude at higher baud rates, then the optical signal quality is improved, but the power consumption of the driver is increased
Solution Approach 1:
Instead of increasing the amplitude of a single electric signal, the patent segments the electrode and applies multiple lower-amplitude electric signals to different segments. Each segment modulates a portion of the data stream with reduced amplitude requirements, achieving sufficient optical signal quality through combined modulation while reducing driver power consumption.
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
This configuration enables ultrahigh-speed optical transmission by effectively managing the phase shifts and bit rates, reducing power consumption, and improving signal quality, thus overcoming the speed limitations of traditional systems.
Implementation Method 1
when an output signal of the driver is provided to the electrode, a phase of the light propagating through the waveguide is changed corresponding to the signal
Implementation Method 2
The optical modulator is provided with optical waveguides constituting a Mach-Zehnder interferometer
Implementation Method 3
M×N phase-shift elements provided along an optical path of the Mach-Zehnder interferometer and respectively configured to shift phases of light propagated in the optical path corresponding to the M×N binary electric signals
Data Source
AI summary
An optical transmitter transmits a modulated optical signal in which each symbol carries M bits. M is an integer larger than one. The optical transmitter includes: a signal generation circuit configured to generate M×N binary electric signals based on transmission data, bit rates of the M×N binary electric signals being equal to each other, N being an integer larger than one, when the optical transmitter multiplexes N optical signals in time-division multiplexing; a Mach-Zehnder interferometer; and M×N phase-shift elements provided along an optical path of the Mach-Zehnder interferometer and respectively configured to shift phases of light propagated in the optical path corresponding to the M×N binary electric signals. The M×N phase-shift segments are comprised of N electrode groups. Each of the N electrode groups includes M or more electrodes to which corresponding M binary electric signals among the M×N binary electric signals are given.