High Contrast Grating Lens for Optical Modulation
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Solution Overview
Problem
Optoelectronic devices, such as VCSELs and photodetectors, often require lenses for proper operation, but existing lens technologies may not efficiently focus light onto optical modulators, especially in back-illuminated configurations, limiting integration and mounting options.
Innovation Solution
A high contrast grating is used as a lens to focus light onto an optical modulator, positioned adjacent to the back surface of a substrate, enabling flip-chip mounting and efficient light modulation by suppressing higher order diffraction modes and providing a predetermined phase front modification.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a traditional lens is used to focus light onto an optical modulator, then light focusing is achieved, but the device complexity increases and integration with back-illuminated configurations is limited
Solution Approach 1:
The patent replaces traditional mechanical lens structures with a high contrast grating (HCG) based optical structure. The HCG uses periodic refractive index variations to achieve light focusing through diffraction and phase modulation rather than mechanical curvature, thereby reducing device complexity while maintaining focusing precision
Solution Approach 2:
The patent changes the optical parameters by using high contrast refractive index variations in the HCG structure. By adjusting the grating period, depth, and refractive index contrast, the patent achieves precise light focusing without requiring complex mechanical lens designs, enabling integration with back-illuminated configurations
2Manufacturing precision
If existing lens technologies are used, then light focusing is achieved, but higher order diffraction modes are not suppressed and modulation efficiency is limited
Solution Approach 1:
The patent applies local quality by designing the HCG structure with spatially varying properties. The grating parameters (period, depth, width) are locally optimized to suppress higher order diffraction modes while enhancing the desired focusing effect, thereby improving modulation efficiency without sacrificing focusing precision
Solution Approach 2:
The patent uses composite material structures in the HCG, combining materials with different refractive indices to create high contrast variations. This composite approach enables precise control over diffraction patterns, suppressing unwanted higher order modes while maintaining effective light focusing and modulation
3Manufacturing precision
If a lens is positioned away from the back surface of the substrate, then light focusing is achieved, but flip-chip mounting and integration options are limited
Solution Approach 1:
The patent transitions the lens function to another dimension by implementing the HCG structure directly on the back surface of the substrate in a planar configuration. This eliminates the need for three-dimensional lens positioning and enables flip-chip mounting while maintaining light focusing precision through in-plane phase modulation
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 high contrast grating lens effectively focuses light onto optical modulators, enhancing light modulation efficiency and enabling integration with optical modulators, particularly in back-illuminated configurations, and allows for flip-chip mounting, improving device performance and integration.
Implementation Method 1
providing a predetermined phase front modification
Implementation Method 2
suppressing higher order diffraction modes
Implementation Method 3
focus light onto an optical modulator
Data Source
AI summary
A high contrast grating optical modulation includes an optical modulator at a front surface of a substrate to modulate received light. The high contrast grating optical modulation further includes a high contrast grating (HCG) lens adjacent to a back surface of the substrate opposite to the front surface to focus incident light onto the optical modulator. The substrate is transparent to operational wavelengths of the focused incident light and the modulated light.