Silicon Dioxide Waveguide Crosstalk Reduction
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Solution Overview
Problem
Silicon-based arrayed waveguide gratings in optical communication devices are sensitive to process errors and temperature, leading to high polarization dependence and crosstalk issues, which hinder their performance in meeting requirements for optical splitters, especially in networks like PON and 40G-PON, and require additional cooling systems increasing power consumption.
Innovation Solution
A waveguide structure using silicon dioxide as a cladding material with a specific axial symmetry design that reduces refractive index fluctuations and polarization dependence, incorporating a ridge silicon dioxide waveguide layer to enhance crosstalk values and reduce temperature sensitivity, allowing for a compact, low-power, and polarization-insensitive device.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If silicon-based waveguide is used, then device size is reduced and manufacturing cost is lowered, but crosstalk performance deteriorates (crosstalk value less than 15 dB)
Solution Approach 1:
The patent changes the material parameter from silicon-based waveguide to silicon dioxide-based waveguide. This material substitution fundamentally alters the refractive index characteristics, reducing process error sensitivity and achieving crosstalk values greater than 25 dB while maintaining compact device size.
Solution Approach 2:
The patent employs silicon dioxide as the waveguide material, creating a composite structure with specific refractive index properties. This material choice combines the advantages of low process error sensitivity, low temperature coefficient, and ability to achieve high crosstalk performance in a compact format.
2Volume of moving object
If silicon-based waveguide is used, then device size is reduced, but temperature sensitivity increases requiring thermoelectric cooler
Solution Approach 1:
The patent changes the material parameter from silicon-based to silicon dioxide-based waveguide, which fundamentally alters the temperature coefficient of the refractive index. Silicon dioxide exhibits lower temperature sensitivity, eliminating the need for thermoelectric cooling while maintaining compact device size.
3Volume of moving object
If silicon-based waveguide is used, then device size is reduced, but polarization dependence increases
Solution Approach 1:
The patent changes the material parameter from silicon-based to silicon dioxide-based waveguide, which modifies the refractive index anisotropy characteristics. This results in reduced polarization dependence, enabling polarization-insensitive operation while maintaining compact device size.
4Reliability
If crosstalk value is increased by increasing waveguide width, then crosstalk performance improves, but device volume increases
Solution Approach 1:
The patent changes the material parameter to silicon dioxide, which inherently reduces process error sensitivity and random phase errors. This allows achieving high crosstalk values (greater than 25 dB) with compact waveguide dimensions, avoiding the need to increase device volume.
5Adaptability or versatility
If silicon-based arrayed waveguide grating is used in PON, then wavelength splitting capability is achieved, but crosstalk value is insufficient (requires at least 25 dB)
Solution Approach 1:
The patent changes the material parameter from silicon-based to silicon dioxide-based waveguide, which fundamentally improves crosstalk performance to greater than 25 dB. This material substitution maintains wavelength splitting capability while meeting the crosstalk requirements for PON applications.
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 proposed waveguide structure achieves a crosstalk value greater than 25 dB, meeting system requirements, and reduces temperature and polarization sensitivity, enabling miniaturization and commercialization of arrayed waveguide gratings without the need for thermoelectric cooling, thus lowering power consumption.
Implementation Method 1
a first silicon waveguide layer 50 configured to transmit the optical signal
Data Source
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AI summary
The present invention provides three waveguide structures, including a protruding-type waveguide structure, a buried-type waveguide structure, and a redeposited-type waveguide structure. The three types of waveguide structures are all applied to a straight waveguide part of an arrayed waveguide in an SOI-based arrayed waveguide grating; the protruding-type waveguide structure includes two axisymmetrically disposed first ends, and the first end is sequentially divided into a first region, a second region, and a third region in a direction toward an axis of symmetry; and the waveguide structure includes a first silicon substrate layer, a second silicon substrate layer, a first silicon dioxide layer, a second silicon dioxide layer, and a first silicon waveguide layer. A corresponding method for producing a waveguide structure, and a waveguide coupling structure are further provided. The waveguide structure and the waveguide coupling structure that are provided in the present invention have advantages of a small size, low polarization dependence, and low temperature sensitivity, and a crosstalk value is greater than 25 dB, which meets a requirement of a passive optical network system, and provides feasibility for commercialization of the arrayed waveguide grating.