Ferroelectric Substrate Integration for Optical Modulator Thinning
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Solution Overview
Problem
Existing optical modulators using periodically poled ferroelectric crystals face challenges in achieving high-speed modulation due to high driving voltages and inaccuracies in forming uniform domain-inverted structures, particularly with thick crystal thickness and rough domain-inverted periods.
Innovation Solution
The optical device integrates a ferroelectric substrate with a support plate via a conductive junction, allowing for thinning of the ferroelectric crystals and precise formation of a periodically poled structure, reducing driving voltage and improving accuracy by shortening the domain-inverted period.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the thickness of ferroelectric crystals is reduced to decrease driving voltage, then high-speed modulation is enabled, but the accuracy of forming uniform domain-inverted structure becomes more difficult to maintain
Solution Approach 1:
A support plate is introduced as an intermediary component between the ferroelectric crystal and the electrode. The support plate provides mechanical stability and a reference surface that enables precise formation of the domain-inverted structure even when the crystal thickness is reduced to achieve high-speed modulation with lower driving voltage.
2Productivity
If the domain-inverted period is shortened to improve conversion efficiency, then wavelength conversion performance is enhanced, but the uniformity of the periodically poled structure over wide surface area becomes difficult to maintain
Solution Approach 1:
The support plate serves as a mediator that provides a stable base for forming the electrode with high precision. This enables the creation of short domain-inverted periods (e.g., 3 μm or less) while maintaining uniformity across the entire surface area, thereby improving conversion efficiency without sacrificing structural uniformity.
Solution Approach 2:
The support plate adds a dimensional reference that extends the fabrication process into a new dimension of precision control. By utilizing the support plate's surface as a reference, the domain-inverted period can be controlled with high accuracy in the thickness dimension while maintaining uniformity across the lateral dimensions.
3Power
If lattice-like electrode is formed on thick ferroelectric crystals to achieve short domain-inverted period, then high voltage can be applied, but the accuracy of periodic structure formation deteriorates
Solution Approach 1:
The support plate acts as an intermediary that enables precise electrode formation even when high driving voltages are applied. The support plate provides a stable reference surface that ensures accurate periodic structure formation, resolving the contradiction between applying high voltage and maintaining manufacturing precision.
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 approach enables high-speed modulation and improved conversion efficiency in optical modulators and wavelength conversion devices by reducing crystal thickness and enhancing the uniformity and accuracy of the periodically poled structure, while also lowering the applied voltage for structure formation.
Implementation Method 1
a junction, held between one major surface of the ferroelectric substrate and one major surface of the support plate opposed to one major surface of the ferroelectric substrate, and which integrates the ferroelectric substrate with the support plate to support the ferroelectric substrate with the support plate
Implementation Method 2
the optical modulator according to the Document 1 is capable of modulating light due to the electro-optical effect
Implementation Method 3
a wavelength conversion device using a periodically poled planar waveguide (MgO:LN (PPMgLN))
Data Source
AI summary
The ferroelectric substrate 11 of ferroelectric crystals, while being supported by the support plate 14 which is thicker than the ferroelectric substrate 11, is integrated with the support plate 14 by letting the junction 13 mediate between one major surface S1A of the ferroelectric substrate 11 and one major surface S1B of the support plate 14, and therefore, it is possible through the flat surface polishing to perform thinning of the ferroelectric substrate 11, namely, the ferroelectric crystals, and as a result, it is possible to obtain the thin periodically poled structure. By the voltage application method, the domain inverted region is formed in the ferroelectric substrate 11 which is made thin.