Optical Modulator Integrated Laser With Dummy RC Impedance Matching
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Solution Overview
Problem
Existing optical modulator integrated laser elements face a trade-off between reducing high-frequency signal reflection and maintaining the bandwidth, as adjusting load impedance to match characteristic impedance narrows the band of high-frequency signals.
Innovation Solution
Incorporating a dummy element unit with resistive and capacitive components in parallel, connected between differential signals and a reference potential, to adjust the overall load impedance to match the transmission line's characteristic impedance, thereby reducing reflection while maintaining bandwidth.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If load impedance is adjusted to match characteristic impedance, then high-frequency signal reflection is reduced, but bandwidth is narrowed
Solution Approach 1:
The load impedance matching network is segmented into multiple components: a first impedance element connected to the differential signal line, and a second impedance element connected to the reference potential line. This segmentation allows independent optimization of each element's characteristics to simultaneously achieve impedance matching and bandwidth preservation.
Solution Approach 2:
Different impedance elements are assigned to different locations in the circuit: the first impedance element is placed near the optical modulator on the differential signal side, while the second impedance element is placed on the reference potential side. Each element has locally optimized properties (different impedance values) to collectively achieve the desired overall effect of reducing reflection while maintaining bandwidth.
2Reliability
If termination resistor is used for impedance matching, then reflection is reduced, but device complexity increases
Solution Approach 1:
The impedance matching function is merged into the existing transmission line structure by adding impedance elements in parallel with the differential signal line and reference potential line, rather than using separate termination resistors. This integration achieves impedance matching while minimizing additional circuit complexity.
Solution Approach 2:
The impedance elements serve multiple functions: they provide impedance matching to reduce reflection, maintain bandwidth, and work together with the optical modulator's differential signaling. This multi-functionality reduces the need for separate dedicated termination components.
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 solution effectively reduces high-frequency signal reflection and secures the same bandwidth as in existing technologies, improving the trade-off between reflection and bandwidth.
Implementation Method 1
adjust the overall load impedance to match the transmission line's characteristic impedance, thereby reducing reflection
Implementation Method 2
includes a resistive component and a capacitive component connected in parallel
Implementation Method 3
an optical modulator that includes a modulation electrode to which one differential signal is input as a positive-phase signal
Data Source
AI summary
An optical modulator integrated laser element includes a laser unit configured to output laser light, an optical modulator that includes a modulation electrode to which one differential signal is input as a positive-phase signal, and a dummy element unit to which another differential signal is input as a negative-phase signal. The optical modulator is connected between the one differential signal and a reference potential. The dummy element unit is connected between the another differential signal and the reference potential, and includes a resistive component and a capacitive component connected in parallel.