Piezoelectric Phase Modulator Asymmetrical Stress Waveguide
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Solution Overview
Problem
Existing phase modulators in photonics and optoelectronics face challenges in achieving high amplitude refractive index variations, leading to limited performance in applications such as LIDAR and telecommunications, due to high power consumption and complex integration issues with solutions like thermo-optical and carrier depletion effects.
Innovation Solution
A phase modulator design featuring a piezoelectric actuator with asymmetrical geometry and positioning, covering at least two sides of the waveguide, to apply mechanical stress synergistically and amplify refractive index variations through a lever arm effect, increasing the state of stress within the waveguide.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by stationary object
If thermo-optical effect is used for phase modulation, then refractive index variation is achieved, but power consumption increases significantly
Solution Approach 1:
The patent replaces the thermo-optical effect (thermal field) with the piezoelectric effect (mechanical field) for phase modulation. The piezoelectric actuator applies mechanical stress directly to the waveguide, inducing refractive index changes through the photoelastic effect without requiring thermal energy input, thereby dramatically reducing power consumption while maintaining effective phase control
Solution Approach 2:
The patent changes the physical mechanism from thermal parameter (temperature) to mechanical parameter (stress). By applying controlled mechanical stress through the piezoelectric actuator, the refractive index is modified directly through stress-optic effects rather than through thermal diffusion, enabling low-power operation with maintained modulation efficiency
2Device complexity
If carrier depletion effect is used for phase modulation, then refractive index variation is achieved, but device complexity increases due to multiple technological steps
Solution Approach 1:
The patent extracts the complex PIN diode structure and carrier depletion mechanism, replacing them with a simpler piezoelectric actuator system. This removes the need for complex semiconductor doping processes and multiple lithography steps while maintaining the core function of refractive index modulation through a more manufacturable approach
Solution Approach 2:
The patent uses a piezoelectric actuator that can be fabricated using standard thin-film deposition techniques, copying the functional requirement of carrier depletion (refractive index change) through a different physical mechanism that is more compatible with conventional microelectronic manufacturing processes
3Reliability
If conventional piezoelectric actuator configuration is used, then phase modulation is achieved, but refractive index variation amplitude remains limited
Solution Approach 1:
The patent employs an asymmetrical actuator configuration where the piezoelectric actuator is positioned offset from the waveguide centerline and applies stress non-uniformly across the waveguide cross-section. This asymmetrical stress distribution creates larger refractive index variations compared to symmetrical configurations, enhancing the phase modulation depth while maintaining a relatively simple single-actuator structure
4Ease of manufacture
If micro-mirror MEMS is used for beam scanning, then beam deflection is achieved, but manufacturing cost and integration complexity increase
Solution Approach 1:
The patent replaces the mechanical MEMS micro-mirror system with an optical phase modulation system using piezoelectric actuators. This substitution eliminates complex mechanical fabrication and assembly processes while achieving beam scanning through phase-based control, reducing manufacturing costs and simplifying integration with standard photonic circuits
Solution Approach 2:
The patent changes the scanning mechanism from physical mirror rotation (mechanical parameter) to optical phase modulation (optical parameter). By controlling the phase of light in different waveguide paths via piezoelectric-induced stress, the system achieves beam deflection without mechanical moving parts, enabling simpler manufacturing and faster response times
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 design significantly enhances refractive index variations, improving the performance of phase modulators and reducing power consumption, while simplifying integration and manufacturing processes.
Implementation Method 1
a piezoelectric actuator configured to apply at least one mechanical stress within said waveguide in response to an electrical bias
Implementation Method 2
By biasing the actuator, a mechanical stress is generated within the waveguide. This mechanical stress then changes the refractive index
Data Source
AI summary
A phase modulator for a light beam comprising a waveguide having a longitudinal axis, and a piezoelectric actuator to apply a mechanical stress within said waveguide in response to an electrical bias, said actuator comprising a first part covering a first side of the waveguide and having a first axis of symmetry essentially parallel to the longitudinal axis. The actuator comprises a second part covering a second side of the waveguide, said second part having a second axis of symmetry essentially parallel to the longitudinal axis.