Folded Mach-Zehnder Modulator for Compact Lithium Niobate Integration
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Solution Overview
Problem
Optical modulators on lithium niobate substrates have large form factors and increased complexity due to the need for additional devices like variable optical attenuators and photodetectors, which complicates chip design and packaging, especially in terms of size and length limitations.
Innovation Solution
A folded Mach-Zehnder modulator design that splits input light beams into multiple paths with a U-turn section and polarization management, using discrete elements such as beam splitters, Mach-Zehnder devices, and U-turn sections to reduce overall package size and increase integration efficiency, allowing for compact integration of complex electro-optic devices.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If additional devices (VOA, PD) are added to the optical modulator, then the functionality and performance are improved, but the device complexity and chip length increase significantly
Solution Approach 1:
The patent integrates multiple discrete optical components (beam splitter, Mach-Zehnder devices, U-turn section, polarisation management section) into a single folded Mach-Zehnder modulator structure on a lithium niobate substrate. This merging approach maintains all required functionalities (polarisation multiplexing, variable optical attenuation, phase modulation) while reducing overall device complexity and eliminating the need for separate interconnection components.
Solution Approach 2:
The patent employs a folded optical path design where the light beam travels through the modulator components in a folded configuration rather than a linear arrangement. This dimensional reorganization allows multiple functional sections to be integrated within a compact footprint, reducing chip length while maintaining all necessary functionalities.
2Adaptability or versatility
If additional devices are integrated on the chip, then the performance is improved, but the chip length and package size increase
Solution Approach 1:
The folded Mach-Zehnder modulator uses a folded optical path configuration where light beams traverse the chip in a bent or folded trajectory rather than a straight line. This allows the optical path length to be extended without increasing the physical chip length, enabling integration of multiple functional devices within compact dimensions that fit standard wafer and package size constraints.
Solution Approach 2:
The patent nests multiple functional sections (beam splitter, Mach-Zehnder devices, U-turn section, polarisation management section) within a compact folded structure. Each functional element is integrated into the folded path, allowing them to be contained within a small chip footprint while maintaining their individual functionalities.
3Adaptability or versatility
If discrete components are used to implement the modulator, then the design flexibility is improved, but the package size increases due to required interconnections
Solution Approach 1:
The patent merges all discrete optical components (beam splitter, Mach-Zehnder devices, U-turn section, polarisation management section) into a single integrated modulator chip. This eliminates the need for separate interconnection components and reduces package size while maintaining design flexibility through the folded configuration that accommodates multiple functional elements.
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 folded design reduces the required chip area by a factor of two, enables the removal of double-sided fiber boots, and maintains device length, facilitating the integration of multiple functions like polarization multiplexing and variable optical attenuation while minimizing optical losses.
Implementation Method 1
a beam splitter configured to split an input light beam into a plurality of light beams
Implementation Method 2
a U-turn section configured to receive light beams from the Mach-Zehnder devices and to change the direction of the light beams by substantially 180 degrees
Implementation Method 3
the U-turn section is configured to bend the light beams in a curved path when changing their direction
Implementation Method 4
a polarisation management section configured to combine light beams received from the U-turn section and to output a polarisation multiplexed phase modulated light beam
Implementation Method 5
output a polarisation multiplexed phase modulated light beam
Data Source
Figure 1
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AI summary
The invention relates to a folded Mach-Zehnder modulator. The modulator may comprise a beam splitter configured to split an input light beam into a plurality of light beams. The modulator may comprise a plurality of Mach-Zehnder devices configured to receive one or more of the plurality of light beams. The modulator may comprise a U-turn section configured to receive light beams from the Mach-Zehnder devices and to change the direction of the light beams by substantially 180 degrees. The modulator may comprise a polarisation management section configured to combine light beams received from the U-turn section and to output a polarisation multiplexed phase modulated light beam.