Mach-Zehnder Modulator Diode Segmentation
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Solution Overview
Problem
Existing Mach-Zehnder modulators require long diodes to achieve a high extinction ratio, leading to increased surface area and energy consumption.
Innovation Solution
A Mach-Zehnder modulator design that uses shorter diodes with a further diode to introduce a phase shift, and applies voltage signals varying between reverse and forward biasing levels to achieve a high extinction ratio, with a control circuit to adjust the phase shift based on optical coupler output.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If long diodes are used to achieve high extinction ratio, then the extinction ratio is improved, but the surface area and energy consumption increase
Solution Approach 1:
The optical modulator is divided into multiple independent optical paths (first optical path with first diode, second optical path with second diode, and third optical path with further diode). Each path contributes to the overall phase modulation, allowing the system to achieve high extinction ratio without requiring any single diode to be excessively long. The segmentation distributes the phase shift requirement across multiple shorter diode elements.
Solution Approach 2:
The patent combines the phase modulation functions of multiple diodes (first diode, second diode, and further diode) working in parallel across different optical paths. The optical coupler merges these paths, and the combined effect of all diodes achieves the required total phase shift for high extinction ratio, equivalent to what would require a single very long diode but with reduced individual diode lengths and total surface area.
2Reliability
If long diodes are used to achieve high extinction ratio, then the extinction ratio is improved, but the energy consumption increases
Solution Approach 1:
The total phase modulation task is segmented across multiple shorter diodes instead of using one long diode. Since energy consumption in diodes is related to their length and operating voltage, using multiple shorter diodes in parallel reduces the total energy required while achieving the same cumulative phase shift effect needed for high extinction ratio.
Solution Approach 2:
The patent changes the operating parameters by applying voltage signals that vary between reverse biasing voltage level and forward biasing voltage level to multiple diodes. This parameter modulation approach across multiple shorter diodes achieves efficient phase control with reduced energy consumption compared to using a single long diode operated at similar voltage levels.
3Area of stationary object
If diode length is reduced, then the surface area and energy consumption are reduced, but the extinction ratio deteriorates
Solution Approach 1:
Instead of relying on a single long diode, the system segments the phase modulation function across multiple shorter diodes. The first diode in the first optical path, the second diode in the second optical path, and the further diode in the third optical path each contribute a portion of the total phase shift, collectively achieving high extinction ratio while maintaining short individual diode lengths and reduced surface area.
Solution Approach 2:
The optical coupler acts as an intermediary that combines the outputs of multiple optical paths with shorter diodes. By merging the light signals from the first, second, and third optical paths, the coupler enables the shorter diodes to collectively achieve the phase modulation effect that would otherwise require longer diodes, thus maintaining high extinction ratio with reduced surface area.
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
The design achieves a high extinction ratio with shorter diodes, reducing surface area and energy consumption while maintaining effective optical modulation, with phase shifts of up to 180° and improved light attenuation.
Implementation Method 1
A first diode adapted to receive a first voltage signal for modifying a phase of a first light signal transmitted through the first optical path
Data Source
AI summary
A Mach-Zehnder modulator (MZM) includes a first optical path with a first diode coupled to a first voltage signal node and configured to modify a phase of a first light signal transmitted through the first optical path. A further diode is positioned in the first optical path and configured to introduce a phase shift to the first light signal. A second optical path includes a second diode coupled to a second voltage signal node and configured to modify a phase of a second light signal transmitted through the second optical path. A first voltage signal carried on the first voltage signal node and a second voltage signal carried on the second voltage signal node each vary between a reverse biasing voltage level and a forward biasing voltage level. An optical coupler is coupled to the first and second optical paths.