Grounded Coplanar Waveguide Layout for Low-Coupling Optical Links
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Solution Overview
Problem
Traditional optical communication systems using microstrip lines and coplanar waveguides suffer from significant cross coupling and substrate depletion, limiting signal transmission speed and quality between chips or within chips.
Innovation Solution
The use of grounded coplanar waveguide (GCPW) as transmission lines in an optical communication system, coupled with a current buffer and transimpedance amplifier (TIA) that includes n-type and p-type metal oxide semiconductor field-effect transistors and a peaking circuit, reduces capacitance effects and cross coupling, enabling faster signal switching and processing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If microstrip lines are used for signal transmission, then the optical communication system can be implemented, but cross coupling between transmission lines increases
Solution Approach 1:
The patent introduces a ground plane as an intermediary element between adjacent transmission lines in the GCPW structure. This ground plane acts as a shield that redirects electromagnetic fields, preventing direct coupling between differential signal lines and reducing cross coupling interference between adjacent channels.
2Reliability
If coplanar waveguide (CPW) is used for signal transmission, then the optical communication system can be implemented, but substrate depletion occurs
Solution Approach 1:
The patent transitions from the traditional planar CPW structure to a three-dimensional GCPW structure by introducing a ground plane beneath the signal lines. This dimensional change confines the electromagnetic fields more effectively within the transmission line structure, preventing field penetration into the substrate and eliminating substrate depletion effects.
3Speed
If traditional transmission lines are used, then the optical communication system can operate, but signal attenuation and distortion increase at high transmission speeds
Solution Approach 1:
The patent changes the fundamental electrical parameters of the transmission line by adopting the GCPW structure, which provides better impedance control and lower loss characteristics. The grounded configuration reduces series resistance and shunt capacitance effects, enabling signals to maintain their integrity at high transmission speeds up to 10 Gb/s and beyond.
Data Source
AI summary
The invention discloses an optical communication system using grounded coplanar waveguide, comprising a current buffer and a transimpedance amplifier (TIA). Transmission lines of the optical communication system have grounded coplanar waveguide (GCPW) structures. The current buffer receives a current signal from a signal source, and outputs the current signal after reducing capacitance effects of the signal source. The TIA converts the current signal to a voltage signal, wherein a first end of the TIA receives the current signal, a second end of the TIAn outputs the voltage signal, and a shunt-shunt feedback circuit is coupled between the first end and the second end. Therefore, the present invention can minimize the circuit area and lower the power consumption as well.