Mach-Zehnder Optical Modulator With Capacitance Phase Control
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Solution Overview
Problem
Existing optical waveguide devices experience phase shifts in differential modulation signals due to asymmetrical shapes and clearance differences between segment electrodes, leading to inconsistent signal propagation.
Innovation Solution
The optical waveguide device incorporates a capacitance adjustment mechanism with dummy electrodes and symmetrically designed modulation electrodes, along with ground electrodes, to adjust phase velocity and suppress phase shifts, using structures like dummy electrodes and capacitance adjustments between modulation and ground electrodes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If segment electrodes with different shapes or different clearances are used to drive the optical waveguide, then the optical waveguide can be miniaturized and operated at low voltage, but phase shifts occur in the differential modulation signals due to asymmetrical electrode configurations
Solution Approach 1:
The patent intentionally introduces asymmetry through dummy electrodes to compensate for the inherent asymmetry in segment electrode configurations. By adding dummy electrodes with specific shapes and clearances to one side, the overall capacitance distribution is balanced, ensuring equal phase velocities in both waveguides while maintaining the miniaturized device structure
Solution Approach 2:
The patent modifies the capacitance parameter by adding dummy electrodes with specific geometric parameters (width, length, clearance) to adjust the electrical characteristics. This changes the capacitance distribution between signal and ground electrodes, thereby equalizing the phase velocities of differential modulation signals without changing the basic segment electrode structure
2Length of moving object
If segment electrodes with different clearances between proximity electrodes are used, then device miniaturization is achieved, but the propagation velocity of differential modulation signals becomes inconsistent causing phase shifts
Solution Approach 1:
The dummy electrodes act as counterweights to balance the capacitance distribution. By adding appropriate dummy electrodes to the side with smaller clearance, the total capacitance is equalized, ensuring that the phase velocities of differential modulation signals are equal despite the asymmetrical clearance distribution
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 stabilizes the phase velocity of differential modulation signals, ensuring consistent signal propagation and reducing phase shifts, thereby enhancing the performance of optical waveguide devices.
Implementation Method 1
a capacitance adjustment mechanism for adjusting a phase velocity of the modulation signal propagating through the modulation electrode is provided between the modulation electrode and the ground electrode which are adjacent to each other
Implementation Method 2
two modulation electrodes are provided to apply a differential modulation signal to each of two branched waveguides configuring the Mach-Zehnder type optical waveguide
Data Source
AI summary
An optical waveguide device in which two modulation electrodes (E1, E2) are provided to apply a differential modulation signal to each of two branched waveguides 10 configuring the Mach-Zehnder type optical waveguide, wherein each of the modulation electrodes includes a plurality of proximity electrodes (PE11 to PE22) disposed in a divided manner along the branched waveguide, a signal electrode (LE1, LE2) for propagating the modulation signal, and a bypass electrode (BE1, BE2) connecting the proximity electrodes and the signal electrode, a ground electrode (G1, G2) is disposed to sandwich the two modulation electrodes (E1, E2), and a capacitance adjustment mechanisms LET11 and LET12 for adjusting a phase velocity of the modulation signal propagating through the modulation electrode is provided between the modulation electrode E1 and the ground electrode G1 which are adjacent to each other.