Thermo-Optic Phase Modulator With DBR Layers for Low-Power Beam Steering
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Solution Overview
Problem
Existing phase modulation devices for laser beam steering, particularly those using optical phased arrays, face challenges in achieving efficient phase control with low power consumption and robustness against changes in incidence angle, often requiring high power due to materials with low thermo-optic coefficients like silicon oxide.
Innovation Solution
A phase modulation device is designed with an active layer made of silicon (Si) or germanium (Ge) having a high refractive index and thermo-optic coefficient, which allows for significant refractive index changes with low power consumption, and includes a high contrast grating layer and distributed Bragg reflector layers to enhance phase control and beam steering efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If materials with low thermo-optic coefficients like silicon oxide are used in the active layer, then the device structure is simpler and easier to manufacture, but high power consumption is required to achieve the desired phase modulation
Solution Approach 1:
The patent changes the material parameter (thermo-optic coefficient) of the active layer from low (silicon oxide) to high (silicon or germanium), enabling significant refractive index changes with minimal power consumption while maintaining manufacturing feasibility through standard semiconductor processes
Solution Approach 2:
The patent employs a composite structure combining the active layer (silicon or germanium) with DBR layers (alternating high and low refractive index materials), creating a multi-material system that achieves both efficient phase modulation and optical wavelength selectivity
2Power
If materials with high refractive index and thermo-optic coefficient are used in the active layer, then phase modulation efficiency is improved and power consumption is reduced, but the device complexity increases due to additional layers and materials
Solution Approach 1:
The active layer serves multiple functions: it provides the primary phase modulation through its high thermo-optic coefficient, acts as a heater when current is applied, and integrates with the DBR structure to achieve wavelength-selective operation, reducing the need for separate components
Solution Approach 2:
The patent uses composite materials where silicon or germanium (active layer) is combined with alternating high and low refractive index materials (DBR layers), creating a structured composite that achieves both phase control and optical filtering in a single integrated device
3Manufacturing precision
If the active layer thickness is increased to improve phase control, then phase modulation range is enhanced, but the device becomes more sensitive to incidence angle variations
Solution Approach 1:
The patent optimizes the active layer thickness parameter to a specific range that provides sufficient phase modulation range while maintaining angular robustness, balancing between phase control precision and adaptability to incidence angle variations
Solution Approach 2:
The DBR layer structure with alternating high and low refractive index materials creates a photonic bandgap that provides wavelength selectivity and angular insensitivity, compensating for the increased angular sensitivity that would otherwise result from a thicker active layer
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 device achieves efficient phase modulation with large phase changes and improved beam steering directivity while reducing power consumption, maintaining robustness against incidence angle variations, by utilizing materials with high thermo-optic coefficients like silicon.
Implementation Method 1
the active layer may include a material having a first thermo-optic coefficient that is greater than a second thermo-optic coefficient of the at least one first low refractive material layer
Implementation Method 2
a first distributed Bragg reflector (DBR) layer including at least one first layer and at least one second layer that are alternately stacked
Data Source
AI summary
A phase modulation device includes an upper reflective layer onto which incident light is incident; a lower reflective layer provided on a lower portion of the upper reflective layer; an active layer provided between the upper reflective layer and the lower reflective layer; a first electrode connected to an upper surface of the active layer; and a second electrode connected to a lower surface of the active layer, wherein the lower reflective layer may include a first distributed Bragg reflector (DBR) layer including at least one first low refractive material layer and at least one first high refractive material layer that are alternately stacked, and the at least one first low refractive material layer has a first refractive index and the at least one first high refractive material layer has a second refractive index that is greater than the first refractive index.