Optical Module 3D Stacked Substrates Size Reduction
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Solution Overview
Problem
The increasing complexity of optical modulators for multi-value processing and optical-polarization division multiplexing in high-capacity optical communication systems leads to a need for more space on the relay substrate, resulting in an enlarged size of the optical module due to the doubling of signal paths and components.
Innovation Solution
The optical module design includes a waveguide substrate with electrodes, a relay substrate, and a terminal substrate mounted on a carrier substrate, with interconnect units that branch to capacitors and resistors, allowing for efficient phase adjustment and bias control without increasing the module size by routing DC electrodes under the waveguide substrate and using inner layer interconnects for DC connections.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If two sets of Mach-Zehnder modulator units are provided for multi-value processing and optical-polarization division multiplexing, then the modulation capability and communication capacity are improved, but the number of signal paths and components is doubled, causing the relay substrate size to increase
Solution Approach 1:
The patent transitions from a planar layout to a three-dimensional stacked architecture by placing the first and second relay substrates on opposite sides of the waveguide substrate. This vertical stacking allows multiple signal paths and components to be arranged in different spatial layers, effectively increasing the modulation capability while preventing the relay substrate area from increasing proportionally.
Solution Approach 2:
The patent divides the relay substrate functionality into separate first and second relay substrates positioned on opposite sides of the waveguide substrate. Each relay substrate handles specific signal paths and components, allowing the system to accommodate multiple Mach-Zehnder modulator units without requiring a single oversized relay substrate.
2Adaptability or versatility
If the number of RF terminals, DC terminals, capacitors, bias resistors, and terminal resistors is doubled, then the modulation functionality is enhanced, but the module size increases
Solution Approach 1:
The patent utilizes the third dimension (vertical stacking) to accommodate the doubled number of components. By placing components on opposite sides of the waveguide substrate, the system can hold more RF terminals, DC terminals, capacitors, bias resistors, and terminal resistors without increasing the module's planar footprint, thus maintaining compact volume.
Solution Approach 2:
The patent embeds multiple functional units within the same module volume by nesting components in different spatial layers. The first and second relay substrates are positioned on opposite sides of the waveguide substrate, allowing components to be nested in a three-dimensional configuration rather than spread out in a single plane.
3Ease of manufacture
If DC electrodes are routed under the waveguide substrate and inner layer interconnects are used, then the layout flexibility is improved and component length is reduced, but the manufacturing complexity increases
Solution Approach 1:
The patent utilizes inner layer interconnects in the carrier substrate to route DC electrodes underneath the waveguide substrate. This three-dimensional interconnect structure provides layout flexibility and reduces component length by allowing connections to pass through the substrate thickness rather than requiring long surface routes, while the complexity is managed through standardized multilayer interconnect techniques.
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 reduces the size and cost of the optical module, improves yield, and allows for flexible layout of components, maintaining high-frequency characteristics while minimizing the length and width of the module.
Implementation Method 1
A first interconnect branch among the second interconnect units includes a capacitor and a terminal resistor
Implementation Method 2
A first interconnect branch among the second interconnect units includes a capacitor and a terminal resistor
Implementation Method 3
a second interconnect branch among the second interconnect units is connected to an interconnect of the carrier substrate via a bias resistor, passes under the waveguide substrate, and extends to a DC electrode, bias-adjusting, on the relay substrate
Implementation Method 4
electrodes that apply an electronic signal to the optical waveguide
Data Source
AI summary
An optical module includes a waveguide substrate including an optical waveguide and electrodes that apply electronic signals to the optical waveguide; a relay substrate disposed adjacent to the waveguide substrate; a terminal substrate disposed adjacent to the waveguide substrate and opposite to the relay substrate across the waveguide substrate; and a carrier substrate on which the waveguide substrate, the relay substrate, and the terminal substrate are mounted. The electrodes have a first interconnect unit from the relay substrate to the terminal substrate via the waveguide substrate and second interconnect units from the first interconnect unit and branching on the terminal substrate. Among the second interconnect units, a first interconnect branch includes a capacitor and a terminal resistor; and a second interconnect branch is connected to an interconnect of the carrier substrate via a bias resistor, passes under the waveguide substrate to a DC electrode for bias-adjusting on the relay substrate.