Optical Receiver Layout for Resonance Band Shifting
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In optical receivers, the connection between the light receiving element and the transimpedance amplifier (TIA) through a wire can lead to resonance frequencies due to inductance and parasitic capacitance, causing non-transmission bands and degrading communication quality, especially at high frequency bands like several tens of GHz or 100 GHz.
Innovation Solution
The optical receiver design includes a light receiving element mounted on a carrier substrate, a dielectric layer, and a base with a conductive surface. A first conductive film with a wiring pattern is connected to the light receiving element, and a second conductive film is between the carrier substrate and the dielectric layer, creating a parasitic capacitance. A conductor with smaller inductance than the wire connects these films, and a transimpedance amplifier is connected through pads. The electrostatic capacitance between the second conductive film and the base is larger than the parasitic capacitance, shifting the resonance frequency to a lower range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a wire is used to connect the light receiving element and the transimpedance amplifier, then electrical connection is achieved, but resonance frequencies occur due to inductance and parasitic capacitance causing non-transmission bands and degrading communication quality
Solution Approach 1:
The patent extracts the harmful inductance by replacing the wire connection with a direct mounting connection. The light receiving element is mounted directly on the carrier substrate with conductive films, eliminating the intermediate wire that causes inductance and resonance. This extraction of the harmful element (wire) resolves the contradiction by maintaining electrical connection while removing the source of resonance interference.
Solution Approach 2:
The patent introduces a conductor with controlled inductance as an intermediary element. The conductor is designed with inductance smaller than that of a wire but larger than a direct connection, serving as a mediator that allows electrical connection while controlling the resonance frequency to a lower range that does not interfere with the signal band. This intermediary approach resolves the contradiction by providing a controlled transition path.
2Reliability
If the inductance of the connection is reduced to avoid resonance, then communication quality improves, but the complexity of the connection structure increases
Solution Approach 1:
The patent merges the connection function with the mounting structure. Instead of using a separate wire for electrical connection, the light receiving element is directly mounted on the carrier substrate with integrated conductive films. This merging of connection and mounting functions reduces the number of components and simplifies the overall structure while achieving low inductance.
Solution Approach 2:
The patent replaces the mechanical wire connection system with a direct semiconductor mounting system. The wire-based mechanical connection is substituted by direct mounting techniques where the light receiving element is bonded to the carrier substrate through conductive films, eliminating the need for wire manipulation and reducing structural complexity.
3Reliability
If a conductor with smaller inductance than the wire is used, then resonance frequency shifts to lower range, but the manufacturing precision requirements increase
Solution Approach 1:
The conductor serves multiple functions: it provides electrical connection, controls inductance to manage resonance frequency, and acts as a mounting element. This multi-functionality reduces the need for separate components and simplifies the manufacturing process, as the same structure achieves multiple objectives without requiring extremely high precision for separate element placement.
Solution Approach 2:
The patent changes the inductance parameter of the connection by using a conductor with specifically controlled inductance characteristics. By adjusting the inductance parameter to be smaller than a wire but larger than a direct connection, the resonance frequency is shifted to a lower range that does not interfere with the signal band, while maintaining manufacturability through standard fabrication 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 suppresses degradation of communication quality by shifting the non-transmission band due to resonance, effectively removing it from the signal frequency band, thereby improving signal waveform integrity and reducing inter-channel crosstalk.
Implementation Method 1
the connection between the light receiving element and the transimpedance amplifier (TIA) through a wire can lead to resonance frequencies due to inductance and parasitic capacitance, causing non-transmission bands
Implementation Method 2
An electrostatic capacitance between the second conductive film and the main surface of the base is larger than the parasitic capacitance
Data Source
AI summary
An optical receiver includes a light receiving element, a carrier substrate, a dielectric layer, a base, a first conductive film, a second conductive film, a conductor, and a transimpedance. The first conductive film is provided between the light receiving element and the carrier substrate. The second conductive film is provided between the carrier substrate and the dielectric layer. A parasitic capacitance is present between the first wiring pattern of the first conductive film and the second conductive film. The conductor is electrically connected to the first wiring pattern and the second conductive film. The transimpedance has a first pad electrically connected to the first wiring pattern through a wire. An electrostatic capacitance between the second conductive film and the main surface of the base is larger than the parasitic capacitance. The inductance of the conductor is smaller than the inductance of the wire.