Optical Receiver Cathode Layout for 100 GHz Resonance Shift
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing optical receivers face challenges in shifting the resonance frequency caused by parasitic capacitance or inductance to a high frequency side, as methods like arranging multiple wirings in parallel are insufficient.
Innovation Solution
The optical receiver design includes a light-receiving element with specific pad configurations and a transimpedance amplifier layout, utilizing cathode and anode wiring patterns, and via connections to effectively shift the resonance frequency to 100 GHz or higher by optimizing the RF current path.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If multiple wirings are arranged in parallel to shift resonance frequency, then the resonance frequency can be increased, but the device complexity and parasitic effects increase
Solution Approach 1:
The cathode wiring is divided into multiple separate wiring patterns (first cathode wiring pattern and second cathode wiring pattern) that are arranged in parallel between the light-receiving element and transimpedance amplifier. This segmentation allows the resonance frequency to be increased while maintaining manageable complexity through modular wiring design
Solution Approach 2:
The patent transitions from a single-plane wiring arrangement to a multi-layer structure with wiring patterns distributed across different layers (light-receiving element layer, insulating layer, and substrate layer). This dimensional change enables parallel wiring configuration that increases resonance frequency while organizing complexity across multiple spatial dimensions
2Reliability
If wiring length and area are increased to improve signal transmission, then the signal quality improves, but parasitic capacitance and inductance increase causing resonance frequency to decrease
Solution Approach 1:
The patent uses multiple cathode wiring patterns in parallel, where each individual wiring pattern can be kept relatively short and small in area, but the collective arrangement provides sufficient signal transmission capability. This partial action approach maintains low parasitic effects in each wiring while achieving reliable signal transmission through the parallel configuration
Solution Approach 2:
Multiple cathode wiring patterns are merged in parallel to create an equivalent wiring structure that has the signal transmission quality of a longer wiring while maintaining the low parasitic characteristics of shorter individual wirings. The combined effect of parallel wirings achieves both reliability and high resonance frequency
3Object-affected harmful factors
If pad size is increased to reduce parasitic effects, then the parasitic capacitance decreases, but the device area increases and crosstalk increases
Solution Approach 1:
The cathode connection is segmented into multiple separate wiring patterns instead of using a single large pad. Each wiring pattern connects to a corresponding pad, allowing the use of smaller pads while maintaining low parasitic capacitance through the parallel wiring configuration
Solution Approach 2:
The patent distributes the cathode connection across multiple layers using via holes, transitioning from a two-dimensional pad expansion to a three-dimensional wiring arrangement. This allows smaller pads on each layer while achieving the same or better parasitic reduction效果 through the multi-layer parallel wiring structure
4Reliability
If wiring density is increased to improve signal transmission, then the signal quality improves, but electromagnetic coupling and crosstalk increase
Solution Approach 1:
The patent applies different wiring patterns and arrangements in different local regions. The cathode wiring patterns are specifically arranged to optimize signal transmission in critical areas while maintaining adequate spacing to reduce electromagnetic coupling. Each local region's wiring configuration is optimized for its specific function, balancing signal quality and crosstalk reduction
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 successfully shifts the resonance frequency to 100 GHz or higher, enhancing the performance of the optical receiver by minimizing parasitic effects and alleviating crosstalk due to electromagnetic coupling.
Implementation Method 1
a light-receiving element (20) having an anode pad (20c) connected to an anode electrode (20a) through an anode wiring pattern (20f)
Data Source
AI summary
An optical receiver according to one embodiment includes a transimpedance amplifier including a first pad, a second pad provided on an insulating layer, connected to a cathode wiring layer through a first via, arranged at a position interposing the first pad, and connected to a first cathode pad of a light-receiving element, and a third pad connected to the second cathode pad of the light-receiving element. The light-receiving element is connected to an anode pad mounted on the transimpedance amplifier and connected through an anode electrode and an anode wiring pattern provided on a surface facing the transimpedance amplifier and a first cathode pad and a second cathode pad connected through a cathode electrode and a cathode wiring pattern and arranged at positions interposing the anode pad.