Electro-Optic Modulator Electrode Layout for Low-Loss Speed Matching
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Solution Overview
Problem
Existing electro-optic modulators face high transmission loss and mismatched transmission speeds of electrical and optical signals due to the use of electro-optic materials with relatively small refractive index and large dielectric constant, leading to sub-optimal working performance.
Innovation Solution
The electro-optic modulator design includes a substrate, isolating layer, and electrode layer with specific electrode arrangements and waveguide configurations, such as GSSG and GSGSG, to create opposite electric fields and minimize signal transmission loss by adjusting electrode and waveguide spacing, impedance, and material thickness to match optical and electrical signal speeds.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If conventional electrode arrangements are used, then device structure is simple, but transmission loss is high and signal speed matching is poor
Solution Approach 1:
The electrode layer is segmented into multiple sub-electrodes (first, second, third, fourth sub-electrodes) arranged in sequence, allowing independent control of electric fields in different waveguide arms. This segmentation enables optimized field distribution that reduces transmission loss while maintaining manageable structural complexity through systematic arrangement.
Solution Approach 2:
The patent introduces a multi-layer vertical structure with substrate, isolating layer, waveguide layer, and electrode layer arranged in sequence. This dimensional organization separates electrical and optical components vertically, reducing interference and enabling independent optimization of each layer to minimize transmission loss without proportionally increasing overall device complexity.
2Reliability
If electro-optic materials with small refractive index and large dielectric constant are used, then material properties are optimized for electro-optic effect, but transmission speed matching between electrical and optical signals deteriorates
Solution Approach 1:
The patent systematically adjusts multiple parameters including electrode spacing, waveguide dimensions, isolating layer thickness, and material composition to optimize both electro-optic effect strength and signal transmission speed matching. By changing these physical parameters, the design achieves compatibility between materials with favorable electro-optic properties and the required speed characteristics.
Solution Approach 2:
The electrode structure is designed to dynamically control electric field distribution through adjustable voltage application on sub-electrodes. This dynamic control allows real-time optimization of the interaction between electrical and optical signals, enabling speed matching adaptation while maintaining high electro-optic modulation efficiency.
3Loss of energy
If electric field strength is enhanced to reduce transmission loss, then transmission loss decreases, but device size increases
Solution Approach 1:
The patent applies electric field enhancement locally at critical interaction regions between electrodes and waveguides rather than uniformly across the entire device. The isolating layer is selectively positioned to confine and concentrate electric fields where needed, achieving transmission loss reduction through localized field strengthening without proportionally increasing overall device volume.
Solution Approach 2:
The design employs a nested multi-layer structure where waveguides are embedded within the electrode layer configuration, and isolating layers are integrated between functional layers. This nesting allows multiple components to occupy overlapping spatial volumes, enhancing electric field interaction density while minimizing the device's external dimensions.
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 design reduces transmission loss and improves working performance by enhancing electric field strength and matching signal transmission speeds, resulting in a more efficient electro-optic modulator with reduced size and improved stability.
Implementation Method 1
The electro-optic effect means that when a voltage is applied to an electro-optic material such as, for example, a lithium niobate crystal, a gallium arsenide crystal, or a lithium tantalate crystal, a refractive index of the electro-optic material will vary, resulting in a change in characteristics of light waves passing through the electro-optic material.
Data Source
AI summary
An electro-optic modulator is provided, which includes a waveguide layer and an electrode layer, where the electrode layer includes: a plurality of first sub-electrodes and a plurality of first connecting electrodes; a plurality of second sub-electrodes and a plurality of second connecting electrodes; a plurality of third sub-electrodes and a plurality of third connecting electrodes; and a plurality of fourth sub-electrodes and a plurality of fourth connecting electrodes, where the plurality of first sub-electrodes and the plurality of fourth sub-electrodes are grounded, the plurality of second sub-electrodes and the plurality of third sub-electrodes receive differential signals, the plurality of first sub-electrodes and the plurality of second sub-electrodes form a first electric field therebetween, and the plurality of third sub-electrodes and the plurality of fourth sub-electrodes form a second electric field therebetween; and the waveguide layer includes a first waveguide arm and a second waveguide arm.