Compact 8-Channel WDM Device Using Beam Folding
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Solution Overview
Problem
Current optical wavelength multiplexing and add/drop devices face challenges in fitting 8 channels into compact form factors like CFP4 and QSFP28, which require a significant reduction in size without compromising performance or increasing complexity.
Innovation Solution
The design involves evenly distributing optical filters and using a reflecting mechanism, such as prisms or mirrors, to ensure all output ports are on one end of the substrate, allowing for a compact packaging that complies with industry standards, and utilizing optical filters to reflect unwanted wavelengths, thereby saving space and reducing the device's width.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the number of WDM channels is increased from 4 to 8 to achieve higher data transmission rates, then the data capacity and bandwidth are improved, but the device size and complexity increase significantly
Solution Approach 1:
The 8-channel WDM device is segmented into two independent 4-channel WDM modules, each handling a separate wavelength range (C-band and L-band). This segmentation allows each module to be optimized independently, reducing the complexity of designing and manufacturing a single 8-channel device while maintaining high data transmission capacity through parallel operation of both modules.
2Productivity
If the number of WDM channels is increased from 4 to 8 to achieve higher data transmission rates, then the data capacity and bandwidth are improved, but the physical size of the device increases
Solution Approach 1:
The patent transitions from a planar 2D layout to a three-dimensional configuration by stacking two 4-channel WDM modules vertically on top of each other. This dimensional change allows the 8-channel device to maintain a compact footprint similar to single-channel devices while accommodating the increased channel capacity through vertical integration rather than horizontal expansion.
3Reliability
If traditional zig-zag free-space optical paths are used for multi-channel WDM, then wavelength separation and filtering are achieved, but the device width and packaging space requirements increase
Solution Approach 1:
The patent replaces the traditional horizontal zig-zag free-space optical path with a vertical three-dimensional optical path configuration. By directing light beams vertically through stacked optical components and using vertical propagation paths, the device achieves effective wavelength separation while minimizing the horizontal footprint, allowing compact packaging in small form-factor modules.
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 enables the creation of compact 8-channel WDM devices that meet the higher data transmission demands while maintaining low back-reflection, low loss, and high reliability, with a smaller footprint and easier manufacturing, supporting higher data rates like 800 Gb/s within the limited form factor.
Implementation Method 1
a dielectric thin film filter transmits a selected wavelength band to a designated channel port and reflect all other wavelengths
Implementation Method 2
Wavelength division multiplexing (WDM) is an exemplary technology that puts data from different sources together on an optical fiber with each signal carried at the same time on its own separate light wavelength
Implementation Method 3
A reflecting mechanism (e.g., a prism or mirrors) is used to ensure all output ports are on end of the substrate
Data Source
AI summary
Techniques for designing compact free-space optical device with all input/output ports on one side are disclosed. Instead of folding a fiber, a beam folding means is provided to turn a light beam to significantly reduce the size of the device. In one embodiment, there are a first collimator, a second collimator, and a beam folding means to turn a light beam from the first collimator back to the second collimator by two turns so that a first light path from the first collimator to the beam folding means and a second light path from the second collimator to the beam folding means are parallel. A substrate is provided to which the first and second collimators and filters are boned thereto.