Multi-Channel Optical Multiplexer Segmentation
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Solution Overview
Problem
Conventional optical multiplexers and demultiplexers face challenges in maintaining compactness and reliability as the number of optical channels increases, leading to geometric error accumulation and increased size, which affects alignment and stability due to pitch errors and index variations from temperature and pressure changes.
Innovation Solution
The design incorporates two structural blocks with mirrors and filters, each combining multiple optical signals into multi-channel signals, which are then combined using a beam combiner, allowing for independent adjustment and reducing geometric errors, while maintaining a compact size similar to systems with fewer channels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the number of optical channels is increased to maximize bandwidth, then the information transmission capacity is improved, but the system size grows considerably in both transverse and longitudinal directions
Solution Approach 1:
The multiplexer is divided into multiple functional blocks (first block with filters 32-36, second block with filters 38-42, third block with filters 44-48) that process different wavelength channels separately. Each block handles a subset of channels, allowing the system to support more total channels while keeping each block's physical dimensions manageable. The segmented architecture prevents the cumulative size growth that would occur in a single monolithic structure.
Solution Approach 2:
The patent employs a three-dimensional arrangement of optical components with optical paths extending in multiple spatial dimensions. The optical signals propagate through a complex 3D path involving multiple reflections off mirrors (40, 52, 64, 76, 88, 100) and passages through filters at different spatial locations. This dimensional approach allows efficient packing of numerous optical components within a compact volume, avoiding the need for a linear expansion of system size.
2Quantity of substance
If the number of wavelengths is increased to add more bandwidth, then the transmission capacity is improved, but the optical path difference becomes relatively large making lens alignment more difficult
Solution Approach 1:
By segmenting the wavelength channels into different functional blocks, each block handles a limited range of wavelengths with controlled optical path differences. The first block handles wavelengths associated with channels 1-5, the second block handles channels 6-10, and the third block handles channels 11-15. This segmentation ensures that no single block experiences excessively large optical path differences that would make alignment difficult.
Solution Approach 2:
The patent incorporates alignment marks (102, 104, 106, 108, 110, 112) on the filters and structural blocks that enable preliminary alignment before final assembly. These pre-positioned reference features allow for accurate lens and filter alignment even as the number of wavelengths increases, eliminating the need for complex post-assembly adjustment procedures.
3Volume of stationary object
If the structural block is designed with a non-right angle alignment axis to reduce dimensions, then the compactness is improved, but the length of the structural block increases with channel number
Solution Approach 1:
The patent utilizes non-coplanar optical paths with mirrors positioned at various angles to redirect light through a compact 3D volume. The optical paths do not follow a simple linear or planar progression but instead navigate through three-dimensional space using reflections. This allows the system to accommodate multiple channels without proportionally increasing the longest dimension of the structural block.
Solution Approach 2:
The functional blocks are arranged in a nested or cascaded configuration where the output of one block feeds into the next. The blocks are positioned to overlap or interleave in space, with later blocks utilizing space not occupied by earlier blocks. This nesting approach maximizes space utilization and prevents linear growth in any single dimension as channels are added.
4Device complexity
If a single block is used to mux all channels, then the device complexity is reduced, but the pitch error accumulates over the increased number of channels
Solution Approach 1:
The multiplexer is divided into multiple independent functional blocks, each handling a subset of wavelength channels. This segmentation isolates the pitch error accumulation to within each individual block rather than across the entire system. Each block can be independently aligned and calibrated, preventing the cumulative error that would occur in a single monolithic block processing all channels.
Solution Approach 2:
Alignment marks are incorporated on each filter and structural block to enable preliminary precision alignment during assembly. These pre-positioned reference features ensure that pitch errors are minimized at each stage of the segmented architecture, and that the modular blocks can be accurately positioned relative to one another without requiring complex global alignment procedures.
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 reduces geometric error accumulation, maintains compact dimensions, and enhances stability by allowing independent adjustment of each structural block, thereby improving the alignment and reliability of multi-channel optical signals.
Implementation Method 1
the first optical signal is reflected by a mirror to a location or spot on the second filter where it is combined with the second optical signal
Implementation Method 2
The second through fourth filters are wavelength-selective filters or beam combiners
Implementation Method 3
a beam combiner configured to combine the first and second multi-channel optical signals into a third multi-channel optical signal, wherein the beam combiner comprises one or more mirrors and one or more filters
Data Source
AI summary
Optical multiplexers, optical demultiplexers, optical modules including the same, and methods of making and using the same are disclosed. The optical multiplexers include first and second structural blocks and a beam combiner. The first and second structural blocks each include at least one mirror and at least one filter, and are configured to combine a plurality of individual optical signals into a multi-channel optical signal. The beam combiner includes one or more mirrors and one or more filters, and is configured to combine the multi-channel optical signals into a further multi-channel optical output signal having the same number of channels as the multi-channel optical signals. The optical demultiplexers are structurally similar to the optical multiplexers, but provide a complementary or reverse function. The present multiplexers and demultiplexers reduce skew and/or accumulation of the geometric error over the channels in the multi-channel optical signal output from the multiplexer or input into the demultiplexer.