Optical Modulator Layout With EM Absorber for Crosstalk Suppression
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Optical modulators experience increased transmission loss and crosstalk due to high directivity modulation signals, especially when a wiring substrate overlaps with a modulation substrate, particularly at microwave frequencies above 60 GHz, leading to signal mixing and interference.
Innovation Solution
The optical modulator incorporates a wiring substrate that overlaps with the modulation substrate, featuring an electromagnetic wave absorption member positioned to face the action portion, connected to ground wiring or electrodes, with specific electrode distances and configurations to suppress crosstalk, and includes a terminator to manage signal propagation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If a wiring substrate is disposed to overlap with a modulation substrate to reduce size, then miniaturization is achieved, but crosstalk of modulation signals increases
Solution Approach 1:
An electromagnetic wave absorption member is introduced as an intermediary between the wiring substrate and modulation substrate. This member absorbs electromagnetic waves that would otherwise cause crosstalk, enabling the overlapping substrate configuration to achieve miniaturization without suffering from signal interference. The absorption member acts as a mediator that permits close proximity while preventing harmful electromagnetic coupling.
Solution Approach 2:
The invention converts the harmful electromagnetic radiation that causes crosstalk into a beneficial solution by using electromagnetic wave absorption material. The absorption member transforms the problematic electromagnetic energy into heat or other non-interfering forms, thereby eliminating crosstalk while maintaining the compact overlapping substrate architecture.
2Device complexity
If wire bonding is used for direct connection to modulation electrode, then connection is simplified, but transmission loss increases at 60 GHz or higher
Solution Approach 1:
The invention transitions from planar wire bonding to a three-dimensional overlapping substrate configuration. The wiring substrate is positioned to overlap with the modulation substrate in the vertical dimension, allowing signal transmission through controlled impedance paths that reduce loss at microwave frequencies while maintaining connection simplicity.
Solution Approach 2:
The invention changes the physical parameters of the connection system by introducing an overlapping substrate geometry with specific spacing and grounding arrangements. This dimensional parameter change enables lower transmission loss at 60 GHz and higher frequencies compared to traditional wire bonding, while the overall connection complexity remains manageable.
3Productivity
If wiring substrate and modulation substrate are disposed close to each other, then integration density increases, but modulation signal crosstalk becomes noticeable
Solution Approach 1:
The electromagnetic wave absorption member serves as a mediator that enables high integration density by allowing close placement of wiring and modulation substrates while preventing signal crosstalk. The absorption material creates an electromagnetic barrier that permits dense integration without compromising signal integrity.
Solution Approach 2:
The invention applies electromagnetic wave absorption material specifically at critical locations where crosstalk would occur, such as near signal vias and electrode connections. This localized application of absorption material provides targeted crosstalk suppression while maintaining overall integration density.
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
Effectively suppresses crosstalk and transmission loss by absorbing electromagnetic interference, ensuring reliable signal transmission even with overlapping substrates.
Implementation Method 1
an electromagnetic wave absorption member is disposed at at least a part of a position facing the action portion in the wiring substrate
Data Source
AI summary
An optical modulator that can suppress crosstalk of a modulation signal even in a case where a wiring substrate is disposed to overlap with a modulation substrate is provided. An optical modulator includes a modulation substrate 1 that includes an optical waveguide and a modulation electrode 10 for modulating a light wave which propagates through the optical waveguide, and a wiring substrate 2 provided with wiring 22 for relaying a modulation signal to be applied to the modulation electrode 10, in which the wiring substrate is disposed to overlap with the modulation substrate to cover an action portion on which modulation is performed by the modulation electrode, and an electromagnetic wave absorption member SH is disposed at at least a part of a position facing the action portion in the wiring substrate.