Silicon Photonics Modulator RF Response Degradation
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Solution Overview
Problem
The existing silicon photonics-based optical modulators face a degradation in their radio frequency (RF) response characteristic due to the connection of RF-designed metal electrodes with DC power supplies, which inhibits the overall RF response.
Innovation Solution
Incorporating a silicon capacitor between the resistor-inductor (RL) and the power supply, or between the RF metal electrodes and the bias power supplies, to prevent degradation of the RF response characteristic by acting as a buffer for the inductive lines and allowing bias voltage supply without affecting the RF frequency response.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If DC power supply is connected directly to RF metal electrodes through inductive lines, then bias voltage can be supplied to operate the optical modulator, but the RF response characteristic is degraded due to the inductive effect of the lines
Solution Approach 1:
A silicon capacitor is introduced as an intermediary component between the inductive line and the RF metal electrode. The capacitor blocks the inductive effect from propagating to the electrode while allowing DC bias voltage to pass through, thus mediating between the power supply connection and the RF performance requirement
Solution Approach 2:
The electrical characteristics of the connection are changed by adding capacitive elements. The silicon capacitor modifies the impedance profile and frequency response of the bias voltage connection, transforming the harmful inductive effect into a manageable RC circuit behavior that maintains RF performance
2Ease of operation
If RF-designed metal electrodes are connected with DC power supplies, then the optical modulator can be operated, but the overall RF response characteristic is inhibited
Solution Approach 1:
The silicon capacitor serves as a mediator that enables DC bias voltage supply to the RF electrode while preventing degradation of RF response. It allows the two conflicting requirements (DC operation and RF performance) to coexist by filtering out the harmful inductive effects
Solution Approach 2:
The connection path is segmented into distinct functional sections: the inductive line for power delivery, the silicon capacitor for filtering and isolation, and the RF electrode for signal modulation. This segmentation allows each component to be optimized for its specific function without compromising the overall system performance
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
The silicon capacitor effectively prevents the degradation of the RF response characteristic, enabling the silicon photonics-based optical modulator to maintain optimal performance even with inductive lines present, ensuring efficient operation and modulation of optical signals.
Implementation Method 1
a silicon capacitor disposed between the RLs and the power supply for preventing a degradation of an RF response characteristic of the silicon photonics-based optical modulator caused by the inductive line
Implementation Method 2
phase shifters disposed between the first RF metal electrodes for optically modulating an optical signal transmitted along an optical waveguide
Data Source
AI summary
A silicon photonics-based optical modulator is disclosed. The optical modulator includes first radio frequency (RF) metal electrodes that operate as a ground, phase shifters disposed between the first RF metal electrodes for optically modulating an optical signal transmitted along an optical waveguide, second RF metal electrodes disposed between the phase shifters for providing an RF electrical signal received from a driving driver located outside of the optical modulator through one end, resistor-inductors (RL) connected to another end of the second RF metal electrodes, an inductive line disposed between the RLs and a power supply for applying a bias voltage to the optical modulator and the driving driver, and a silicon capacitor disposed between the RLs and the power supply for preventing a degradation of an RF response characteristic of the silicon photonics-based optical modulator caused by the inductive line.