Optical Modulator DC Electrode Thickness for Crosstalk Reduction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing Mach-Zehnder optical modulators suffer from electrical crosstalk due to noise signals from adjacent DC portion electrodes, which limits high-frequency characteristics and narrows the frequency band.
Innovation Solution
The optical modulator features a substrate with an electro-optical material layer, a buffer layer, and electrodes where the film thickness of the DC portion electrode is smaller than that of the RF portion electrode, effectively reducing electrical crosstalk and improving high-frequency characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the film thickness of the DC portion electrode is made equal to or larger than that of the RF portion electrode, then the manufacturing process is simplified, but electrical crosstalk occurs due to noise signals from the DC electrode affecting the RF electrode
Solution Approach 1:
The patent applies different film thicknesses to different portions of the electrode structure. Specifically, the DC portion electrode is designed with a film thickness of 0.1 to 3.0 μm, which is equal to or smaller than that of the RF portion electrode (1.0 to 8.0 μm). This local differentiation allows the DC electrode to have reduced noise emission while the RF electrode maintains its signal transmission capability, thereby suppressing electrical crosstalk without requiring complete redesign of the entire electrode system.
2Object-affected harmful factors
If the film thickness of the DC portion electrode is reduced to suppress electrical crosstalk, then high-frequency characteristics improve, but the electrode becomes more susceptible to damage and manufacturing precision requirements increase
Solution Approach 1:
The patent optimizes the film thickness parameter of the DC portion electrode to a specific range (0.1 to 3.0 μm) that balances crosstalk suppression and reliability. By carefully controlling this parameter within the specified range, the design achieves sufficient noise reduction while maintaining adequate mechanical strength and manufacturing feasibility. The lower bound of 0.1 μm ensures the electrode remains functional, while the upper bound of 3.0 μm ensures adequate crosstalk suppression.
3Object-affected harmful factors
If the film thickness of the DC portion electrode is made smaller than the RF portion electrode, then electrical crosstalk is suppressed and high-frequency characteristics are improved, but the manufacturing process becomes more complex
Solution Approach 1:
The patent implements local quality differentiation by applying distinct film thickness specifications to different electrode portions. The DC portion electrode is designed with thickness of 0.1 to 3.0 μm while the RF portion electrode has thickness of 1.0 to 8.0 μm. This localized parameter variation targets the specific problem of electrical crosstalk without requiring complex structural modifications throughout the entire device, thereby limiting the increase in device complexity to only the necessary electrode thickness variation.
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 configuration sufficiently suppresses electrical crosstalk, enhances high-frequency characteristics, and widens the bandwidth of the optical frequency band, while also reducing material usage and costs.
Implementation Method 1
an electro-optical material layer formed on a predetermined region of the substrate
Data Source
AI summary
An optical modulator includes a substrate; an electro-optical material layer formed on a predetermined region of the substrate; a buffer layer formed on the substrate which is provided so as to cover the electro-optical material layer; and an electrode formed on the buffer layer. The electro-optical material layer has a RF portion optical waveguide which is applied with a modulation signal and is patterned, and a DC portion optical waveguide which is applied with a DC voltage and is patterned. The electrode has an RF portion electrode formed on the buffer layer where the RF portion optical waveguide is located and a DC portion electrode formed on the buffer layer where the DC portion optical waveguide is located. The film thickness of the DC portion electrode is smaller than the film thickness of the RF portion electrode.