Single-Package Dual Optical-Function Interleaver
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Solution Overview
Problem
Current optical communication systems face limitations in reducing channel spacing due to the cost and performance constraints of multiplexer and de-multiplexer devices, particularly in dense wavelength division multiplexing (DWDM), where standard channel spacing is 100 GHz, and achieving uniform loss and minimal chromatic dispersion across multiple channels is challenging.
Innovation Solution
A four-fiber collimator is coupled with a single interleaver or etalon structure to provide the functionality of two dual-fiber interleavers or etalons, aligning fibers in specific geometries to produce aligned or offset output peaks, allowing for reduced channel spacing and increased bandwidth while minimizing manufacturing costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If standard multiplexer and de-multiplexer devices are used with 100 GHz channel spacing, then manufacturing cost is controlled, but communication capacity is limited
Solution Approach 1:
The patent combines the functionality of two separate dual-fiber interleavers into a single package containing one three-port interleaver and one four-fiber collimator. This merging reduces the number of discrete components needed, lowering manufacturing costs while maintaining the capability to handle reduced channel spacing for increased communication capacity
Solution Approach 2:
The single-package device performs multiple functions: it acts as both an interleaver and a collimator system, providing wavelength separation and spatial beam control simultaneously. This multi-functionality eliminates the need for separate devices, reducing overall system cost while enabling higher channel density
2Area of stationary object
If thin-film filtering technology is used, then wide bandwidth is achieved, but uniform loss and chromatic dispersion control deteriorate
Solution Approach 1:
The patent introduces an etalon structure as an intermediary optical element that provides precise wavelength-selective feedback. The etalon's resonant cavities create sharp transmission peaks at specific wavelengths, enabling uniform loss characteristics and minimal chromatic dispersion across channels while maintaining wide bandwidth through proper cavity design
3Reliability
If array waveguide gratings are used, then uniform loss and minimal chromatic dispersion are achieved, but bandwidth is reduced
Solution Approach 1:
The patent modifies the optical path length parameter within the etalon cavity to tune the transmission spectrum. By adjusting the cavity length and refractive index, the system achieves both wide bandwidth and uniform loss characteristics, overcoming the bandwidth limitation of array waveguide gratings while maintaining their dispersion advantages
4Productivity
If channel spacing is reduced below 100 GHz, then communication capacity increases, but manufacturing cost increases dramatically
Solution Approach 1:
The patent segments the optical spectrum into distinct wavelength channels using the interleaver's wavelength-selective reflection and transmission properties. The four-fiber collimator further segments the spatial distribution of these channels, enabling reduced channel spacing without requiring expensive custom-manufactured components for each channel
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 configuration enables the production of two interleavers or etalons in a single package, reducing material and labor costs, and achieving precise alignment of output peaks, thereby enhancing communication capacity and reducing chromatic dispersion, while maintaining low insertion loss.
Implementation Method 1
the core optics of a single optical phase-optics unit... a beam-splitter surface adapted to produce reflected beams and transmitted beams... a mirror surface optically coupled to the beam-splitter surface... an etalon with a tuner optically coupled to the beam-splitter surface
Implementation Method 2
an etalon structure... The etalon 16 typically includes a tuner and consists preferably of a Gires-Tournois etalon
Data Source
AI summary
A four-fiber collimator is coupled to the optics of a single interleaver to produce the functionality of two co-packaged interleavers. Two fibers of the collimator are coupled to the core optics of a single interleaver to produce two pairs of output beams. The other two fibers of the collimators are coupled to receive the reflection output beams. The geometry of the optical fibers in the bundle is controlled to produce interleaver outputs with no offset. In another embodiment two fibers of the four-fiber collimator are coupled as inputs to and the other two fibers as outputs from a Fabry-Perot etalon. The geometry of the fibers and the focal length of the collimator are controlled to produce two outputs with peaks offset by a predetermined amount.