Spectrally Adjustable Filter Using Tiltable Mirror
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Solution Overview
Problem
Current optical filtering devices in WDM systems face challenges due to long optical path lengths and high costs associated with imaging configurations, which compromise spectral performance and size requirements.
Innovation Solution
A spectrally adjustable filter apparatus using a tiltable reflective element and optical elements to change the relative angles of propagation, allowing for non-imaging configurations that reduce optical path length while maintaining spectral performance, employing prisms and lenses to disperse spectral components at different angles and preserve collimation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If imaging configurations are used with lenses to filter spectral components, then spectral performance is improved, but optical path length increases and device size increases
Solution Approach 1:
The patent extracts the essential function of spectral filtering from the traditional imaging configuration. By removing the requirement for functional elements to be placed at focal points, the design eliminates the need for long optical paths while maintaining spectral filtering capability through direct placement of elements in the dispersed beam path.
Solution Approach 2:
The patent transitions from a one-dimensional imaging approach (where elements are placed at focal distances along the optical axis) to a two-dimensional approach where elements are positioned in the spectral dispersion plane. This allows spectral filtering to occur at different spatial locations without requiring long propagation distances.
2Measurement precision
If imaging configurations with lenses are used, then spectral performance is improved, but device cost increases
Solution Approach 1:
The patent removes the requirement for expensive aspheric lenses by extracting the imaging function entirely. The design achieves spectral filtering without needing precision-corrected lenses, thereby reducing manufacturing costs while maintaining performance through the non-imaging configuration.
3Measurement precision
If functional elements are placed at focal lengths of imaging elements, then spectral filtering is achieved, but device size increases
Solution Approach 1:
The patent repositions functional elements from the axial dimension (at focal distances) to the transverse dimension (in the spectral dispersion plane). This allows the same spectral filtering function to be achieved within a much more compact footprint by utilizing the spatial distribution of dispersed wavelengths.
4Measurement precision
If aspheric lenses are used to reduce aberration, then spectral performance is improved, but cost increases
Solution Approach 1:
The patent extracts the spectral filtering function from the lens system entirely, eliminating the need for aspheric lenses. The design achieves aberration-free spectral filtering through direct geometric dispersion without requiring complex lens corrections, thereby reducing cost while maintaining performance.
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
Enables compact, low-cost spectral filters and monitors with improved spectral resolution and reduced size, maintaining key performance advantages of imaging configurations without the associated costs and length limitations.
Implementation Method 1
a spectrally dispersive element configured to receive the input beam at a location at which the central ray of the input beam is incident at different points on the spectrally dispersive element for each of the tilt orientations, and configured to disperse spectral components of the input beam at different respective angles in a spectral plane
Implementation Method 2
a first reflective element configured to tilt to multiple tilt orientations that each corresponds to a different angle of propagation of at least one input beam
Data Source
AI summary
For spectrally filtering at least one input beam, a first reflective element is configured to tilt to multiple tilt orientations that each corresponds to a different angle of propagation of at least one input beam. One or more optical elements are configured to change at least some of the relative angles of propagation of the input beam for different tilt orientations of the first reflective element. A spectrally dispersive element is configured to receive the input beam at a location at which the central ray of the input beam is incident at different points on the spectrally dispersive element for each of the tilt orientations, and configured to disperse spectral components of the input beam at different respective angles in a spectral plane. The first reflective element is configured to tilt to select at least one and fewer than all of the dispersed spectral components to be directed to a selected output path.