Bendable Grating Bandwidth Control via Decoupled Actuation
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Solution Overview
Problem
Current optical grating systems lack precise control over bandwidth selection, particularly in selecting both a minimum and maximum bandwidth of wavelengths centered on a specific center wavelength, which is essential for advanced optical systems requiring precise interference patterns and spectral control.
Innovation Solution
The system employs a dispersive optical element with a reflective face that can be bent in two directions, vertically and horizontally, using decoupled actuator forces to minimize interference between bending mechanisms, allowing for independent control of bandwidth selection through flexures and pressurized fluid forces, enabling precise adjustment of grating lines to achieve desired bandwidths.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a typical grating is used to narrow a light beam, then the beam is narrowed to a selected center wavelength, but the bandwidth of wavelengths in the narrowed beam cannot be precisely controlled
Solution Approach 1:
The patent applies dynamics by making the grating bendable rather than rigid. The grating can be dynamically bent in two independent directions (first and second directions perpendicular to the grooves) to adjust the bandwidth. This allows the system to transition from a static wavelength selection device to a dynamic device that can control both center wavelength and bandwidth independently by applying controlled forces in different directions.
Solution Approach 2:
The patent introduces another dimension of control by enabling bending in two independent directions (first direction and second direction, both perpendicular to grooves but orthogonal to each other). This dimensional extension allows independent control of bandwidth parameters (E95 and FWHM) in addition to center wavelength selection, transforming a one-dimensional wavelength selection into a multi-dimensional spectral control capability.
2Measurement precision
If the beam expander and grating curvature are tuned for precise center wavelength selection, then the maximum bandwidth is narrowed to less than 1.0pm, but the ability to select both minimum and maximum bandwidth independently is lost
Solution Approach 1:
The patent makes the grating dynamically adjustable by applying forces in two independent directions. The first direction controls one bandwidth parameter (E95) while the second direction controls another parameter (FWHM), allowing independent adjustment of both minimum and maximum bandwidth limits while maintaining precise center wavelength selection.
Solution Approach 2:
The patent changes the physical state of the grating from rigid to flexible/bendable, enabling continuous parameter adjustment. By varying the degree and direction of bending, the system can independently control multiple bandwidth parameters (E95, FWHM) and center wavelength, providing extensive operational flexibility without sacrificing precision.
3Adaptability or versatility
If distorting forces are applied to the grating to control bandwidth, then bandwidth selection is improved, but interference between distorting mechanisms increases
Solution Approach 1:
The patent segments the distorting mechanism into two independent directional components (first direction and second direction, both perpendicular to grooves). Each direction can be controlled separately by independent actuators, allowing bandwidth parameters to be adjusted without significant interference between control mechanisms. This segmentation reduces coupling complexity while maintaining versatile bandwidth control.
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 approach allows for precise selection and control of bandwidth, expanding the range from less than 200 fm to greater than 1500 fm, maintaining spectral integrity and minimizing interference between horizontal and vertical bending forces, thus addressing the limitations of existing systems.
Implementation Method 1
The expanded source light beam includes multiple wavelengths of light that are diverging at different angles relative to the beam expander and impinge on the reflecting surface in corresponding different locations. The selected grating line reflects a narrowed light beam including only the corresponding reflected wavelength toward the beam expander
Implementation Method 2
The grating has a reflecting surface with many grating lines. The selected grating line reflects a narrowed light beam including only the corresponding reflected wavelength toward the beam expander at the appropriate angle
Data Source
Figure 1
Figure 2A~2C
Figure 3
AI summary
A mechanism for bandwidth selection includes a dispersive optical element having a body including a reflective face of dispersion including an area of incidence extending in a longitudinal axis direction along the reflective face of the dispersive optical element The body also includes a first end block, disposed at a first longitudinal end of the body and a second end block, disposed at a second longitudinal end of the body, the second longitudinal end being opposite the first longitudinal end The bandwidth selection mechanism also includes a first actuator mounted on a second face of the dispersive optical element, the second face opposite the reflective face, the first actuator having a first end coupled to the first end block and a second end coupled to the second end block, the first actuator being operative to apply equal and opposite forces to the first end block and the second end block