Optical Modulator Capacitance Matching for Stable Phase Velocity
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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 propagation velocities.
Innovation Solution
The optical waveguide device incorporates capacitance adjustment mechanisms, such as dummy electrodes and symmetric electrode designs, to adjust phase velocities and match capacitances, thereby stabilizing the propagation of differential modulation signals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If asymmetrical segment electrode shapes or different clearances between proximity electrodes are used, then the device complexity is reduced and ease of manufacture is improved, but phase shift occurs in differential modulation signals due to inconsistent propagation velocities
Solution Approach 1:
The patent intentionally introduces asymmetry through dummy electrodes to compensate for the inherent asymmetry in segment electrode shapes or clearances. By adding capacitive elements (dummy electrodes) to the electrode with smaller capacitance, the overall capacitance values are equalized, ensuring consistent propagation velocities and eliminating phase shifts in differential modulation signals.
2Ease of manufacture
If different shapes of segment electrodes are used, then manufacturing is simplified, but phase velocity consistency between electrodes deteriorates
Solution Approach 1:
The patent changes the capacitance parameter by adding dummy electrodes with specific capacitance values to compensate for differences in segment electrode shapes. This parameter adjustment equalizes the total capacitance of both electrodes, thereby standardizing the propagation velocity of differential modulation signals despite the asymmetrical shapes of the segment electrodes.
3Ease of manufacture
If clearances between proximity electrodes are made different, then manufacturing tolerances are relaxed, but signal propagation velocity becomes inconsistent
Solution Approach 1:
The patent applies preliminary anti-action by pre-calculating and compensating for the capacitance differences caused by varying clearances between proximity electrodes. Dummy electrodes are designed with specific capacitance values to counterbalance the effects of different clearances, ensuring that the total capacitance remains equal and propagation velocities remain consistent, thereby maintaining signal propagation precision despite relaxed manufacturing tolerances.
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 suppresses phase shifts and ensures consistent signal propagation, enhancing the performance of optical modulation devices and transmission apparatuses.
Implementation Method 1
two branched waveguides configuring the Mach-Zehnder type optical waveguide are each provided with two modulation electrodes for applying a differential modulation signal
Implementation Method 2
a capacitance adjustment mechanism for adjusting a phase velocity of the modulation signal propagating through the modulation electrode is provided on at least one of the two modulation electrodes
Data Source
AI summary
An optical waveguide device in which an optical waveguide including at least one Mach-Zehnder type optical waveguide is formed on a substrate, and two branched waveguides 10 configuring the Mach-Zehnder type optical waveguide are each provided with two modulation electrodes (E1, E2) for applying a differential modulation signal, 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, and a capacitance adjustment mechanism (DE) for adjusting a phase velocity of the modulation signal propagating through the modulation electrode is provided on at least one of the two modulation electrodes (E1, E2).