Optical Modulator Glass Dummy Blocks Mitigate Pyroelectric Effects
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Solution Overview
Problem
Ferroelectric substrates in optical modulators experience pyroelectric effects due to temperature changes, leading to uneven electric charge distribution and electric discharging between the substrate and dummy blocks, which deteriorate the quality of modulated optical signals.
Innovation Solution
The use of glass dummy blocks with Mohs hardness less than the ferroelectric substrate and without pyroelectric effects, which are formed to protect the optical waveguides and prevent electric discharging by mitigating pyroelectric effects, while also having a suitable abrasion level to minimize manufacturing costs and maintain optical signal quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If dummy blocks are made from ferroelectric material to protect optical waveguides, then protection function is provided, but pyroelectric effects cause electric charge accumulation and discharging that deteriorate optical signal quality
Solution Approach 1:
The patent replaces the ferroelectric dummy blocks with glass dummy blocks that have lower hardness. These glass blocks serve the protective function during dicing but are designed to be softer than the substrate, allowing them to be removed or replaced without damaging the optical waveguides. The glass material does not exhibit pyroelectric effects, eliminating the electric charge accumulation problem.
Solution Approach 2:
The patent changes the material parameter of the dummy blocks from ferroelectric material to glass material with specific hardness properties. By selecting glass with Mohs hardness between 3-5 (lower than the LiNbO3 substrate), the dummy blocks provide protection during manufacturing while avoiding the pyroelectric effect that causes signal deterioration. This parameter change resolves the contradiction between protection function and signal quality.
2Strength
If dummy blocks are made from hard material to protect optical waveguides during dicing, then protection function is improved, but cutting tool abrasion increases and manufacturing cost rises
Solution Approach 1:
The patent optimizes the hardness parameter of dummy blocks by selecting glass materials with Mohs hardness between 3-5, which is lower than the LiNbO3 substrate (Mohs hardness ~5-6). This parameter selection provides sufficient protection during dicing while minimizing abrasion of cutting tools, thereby reducing manufacturing costs.
Solution Approach 2:
The glass dummy blocks are designed as temporary protective elements used during the dicing process. Their lower hardness compared to traditional ferroelectric dummy blocks reduces tool wear, and they can be removed after serving their protective purpose, making them a cost-effective solution.
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 solution effectively reduces pyroelectric effects, preventing electric discharging and maintaining the quality of modulated optical signals, while also reducing the abrasion of cutting tools and manufacturing costs by selecting appropriate glass materials with specific hardness and abrasion levels.
Implementation Method 1
ferroelectric substrates in optical modulators experience pyroelectric effects due to temperature changes, leading to uneven electric charge distribution and electric discharging between the substrate and dummy blocks
Implementation Method 2
an optical waveguide is formed in the vicinity of the surface of the substrate 1
Implementation Method 3
Ferroelectrics that have a strong electro-optic effect are used for optical devices that convert an electric signal into an optical signal
Data Source
AI summary
An optical modulator includes: a ferroelectric substrate in which an input optical waveguide, a pair of branched optical waveguides, and an output optical waveguide are formed; a signal electrode that is formed in a vicinity of at least one of the pair of branched optical waveguides; a first protection member that is attached to an input end of the ferroelectric substrate in which the input optical waveguide is formed; and a second protection member that is attached to an output end of the ferroelectric substrate in which the output optical waveguide is formed. The first protection member and the second protection member have a Mohs hardness that is less than or equal to a Mohs hardness of the ferroelectric substrate, and are formed of a glass material that does not have a pyroelectric effect.