Stress-Optic Phase Controller Dome Structure
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Solution Overview
Problem
Existing phase controllers for optical signals in surface waveguides face challenges with high power consumption, slow operation, and high cost due to the need for long interaction lengths and high voltages, making them unsuitable for many applications.
Innovation Solution
A stress-optic phase controller with a carefully shaped dome structure in the upper cladding, eliminating the flat portion above the waveguide core, allows for efficient stress induction using a piezoelectric element, reducing the drive voltage and interaction length while maintaining low power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If a traditional TO phase controller is used to control the phase of light signals, then phase control capability is achieved, but power consumption becomes very high (>100 mW) and operation speed becomes slow
Solution Approach 1:
The patent replaces the thermal field mechanism (TO effect) with a mechanical stress field mechanism (SO effect). By using a piezoelectric element to generate mechanical stress instead of thermal heating, the system achieves fast response (microsecond scale) and low power consumption while maintaining phase control capability. The piezoelectric element converts electrical energy directly to mechanical stress, eliminating the slow thermal diffusion process.
Solution Approach 2:
The patent changes the fundamental operating parameter from temperature (TO effect) to mechanical stress (SO effect). This parameter change enables the use of piezoelectric materials that respond rapidly to electrical signals, thereby improving both speed and power efficiency. The stress-induced refractive index change achieves the same phase modulation function with superior performance characteristics.
2Power
If a stress-optic phase controller with conventional flat dome structure is used, then phase control is achieved, but drive voltage requirements are high and interaction length must be long
Solution Approach 1:
The patent applies curvature to the dome structure by eliminating the flat top portion and creating a continuously curved surface. This curved geometry concentrates the mechanical stress more effectively in the underlying waveguide core, enhancing the photo-elastic effect. The curved dome shape allows for more efficient stress distribution, reducing the required drive voltage and interaction length compared to conventional flat-dome structures.
Solution Approach 2:
The patent creates a localized stress concentration region by shaping the dome to have no flat portion, ensuring that the stress is focused precisely where needed in the waveguide core. This local optimization of stress distribution improves the efficiency of the photo-elastic effect, allowing for reduced drive voltage and shorter interaction lengths while achieving the required phase shift.
3Reliability
If electro-optic-based phase controllers are used to control light phase, then phase control capability is achieved, but excess loss becomes significant due to optical mode perturbation
Solution Approach 1:
The patent replaces the electro-optic effect (which directly perturbs the optical mode) with a stress-optic effect using piezoelectric materials. The piezoelectric element generates mechanical stress that indirectly modifies the refractive index through the photo-elastic effect, without significantly disturbing the optical mode. This substitution maintains phase control capability while minimizing excess optical loss.
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 enables phase changes greater than 2π at moderate voltages over short interaction lengths, offering a fast, space-efficient, and low-power solution for phase control in optical waveguides.
Implementation Method 1
a piezoelectric element configured to induce a refractive index change in the underlying waveguide by imparting a stress in at least a portion of its material when energized by a control signal
Implementation Method 2
stress-optic-based phase-tuning capability exploiting the photo-elastic effect has been demonstrated by incorporating a piezoelectric element disposed on a surface waveguide structure
Implementation Method 3
a carefully shaped dome structure in the upper cladding, eliminating the flat portion above the waveguide core, allows for efficient stress induction using a piezoelectric element
Data Source
AI summary
The present disclosure is directed to systems and methods for controlling the phase of at least one light signal in a planar-lightwave circuit (PLC) via a stress-optic (SO) phase controller. SO phase controllers in accordance with the present disclosure include a stress-inducing element disposed on a dome-shaped surface of the upper cladding of an integrated-optics-based waveguide, where the dome surface includes little or no linear portion. Such a dome-shaped surface improves the effectiveness with which the stress-inducing element can impart stress in the waveguide materials, thereby reducing the drive voltage and/or interaction length required to induce a given phase shift as compared to the prior art.