Optical Band-Stop Filter Using Segmented Transfer Functions
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Solution Overview
Problem
Current optical band-stop filters lack sufficient selectivity and tunability, particularly in terms of spectral width and central wavelength, making them unsuitable for finer filtering applications such as manipulating orthogonally multiplexed optical sub-bands in optical transmission networks.
Innovation Solution
A band-stop optical filtering device comprising duplicating means and two optical filtering units with specific transfer functions, allowing for precise suppression of optical bands and adjustable notch filtering, utilizing band-pass filters with rectangular profiles for enhanced selectivity and tunability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If current optical band-stop filters are used, then the device complexity is reduced, but the selectivity and tunability are insufficient for finer filtering applications
Solution Approach 1:
The optical band-stop filter is segmented into two separate optical band-pass filters with complementary transfer functions. Each filter handles a specific portion of the spectral range, allowing independent optimization of selectivity and tunability while maintaining manageable device complexity through modular architecture
Solution Approach 2:
The dual-filter configuration provides multi-functionality by enabling both high-selectivity filtering and broad spectral coverage. The system can selectively suppress different optical sub-bands by adjusting the transfer functions of the individual filters, making it adaptable to various filtering requirements without requiring multiple dedicated devices
2Manufacturing precision
If the spectral width of the filter is reduced for finer filtering, then the selectivity is improved, but the device size increases making it unusable in practice
Solution Approach 1:
By dividing the filtering function across two separate band-pass filters, each filter can be optimized for a specific spectral range with appropriate selectivity. This segmentation allows the system to achieve fine spectral filtering without requiring a single oversized filter component
Solution Approach 2:
The patent transitions from a single-dimension filter design to a two-dimensional filtering approach by combining two filters with different transfer function characteristics. This dimensional expansion in the filter configuration space enables fine spectral selectivity while maintaining compact physical dimensions
3Manufacturing precision
If the transfer function is made more selective with narrower bandwidth, then the filtering precision is improved, but the tunability range is reduced
Solution Approach 1:
The system achieves both high filtering precision and broad tunability through the complementary design of two band-pass filters. By independently adjusting the transfer functions of each filter, the system can precisely suppress specific sub-bands while maintaining the ability to tune across a wide spectral range
Solution Approach 2:
The filter system incorporates dynamic adjustability by allowing independent modification of the transfer functions for each band-pass filter. This dynamic configuration enables the system to adapt to different filtering requirements, switching between high-selectivity narrowband filtering and broader spectral filtering as needed
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 solution provides improved selectivity and tunability, enabling precise suppression of optical sub-bands within optical signals, allowing for finer filtering and manipulation of multiplexed sub-bands without impacting neighboring bands, which is not achievable with existing technologies.
Implementation Method 1
duplicating means suitable for duplicating an optical signal into a first duplicated optical signal and a second duplicated optical signal
Implementation Method 2
a first optical filtering unit, connected to the first output port of the duplicating means, having a transfer function with a decreasing part between a first cut-off wavelength and a first extinction wavelength
Implementation Method 3
a second optical filtering unit, connected to the second output port of the duplicating means, having a transfer function with an increasing part between a second extinction wavelength and a second cut-off wavelength
Implementation Method 4
coupling means, connected to the first and second optical filtering units and arranged to combine the optical signals filtered by said optical filtering units
Data Source
Figure 1
Figure 2A
Figure 2B~2C
AI summary
The invention relates to an optical pass-band filtering device (10) comprising: duplication means (11) able to provide duplicates of an optical signal to at least a first and a second output port; a first optical filtering unit (13) that is connected to the first output port of the duplication means, said unit having a transfer function that decreases between a first pass wavelength and a first cut-off wavelength; a second optical filtering unit (15), connected to the second output port of the duplication means, said unit having a transfer function that increases between a second cut-off wavelength and a second pass wavelength, the second cut-off wavelength being higher than the first cut-off wavelength; and coupling means (19) connected to the first and second optical filtering units and arranged so as to combine the optical signals filtered by said optical filtering units in order to obtain a filtered optical signal in which the optical band located between the first and second cut-off wavelengths is removed. The invention also relates to an insertion/extraction device and an insertion/extraction node using such a filtering device and the corresponding methods.