Optical Multiplexer Assembly With Birefringent Alignment Stability
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Solution Overview
Problem
Existing optic multiplexing/demultiplexing devices face challenges in maintaining precise alignment under harsh environmental conditions, such as high temperature and humidity, due to susceptibility to outside forces and vibrations, leading to increased optical losses and mechanical stress.
Innovation Solution
Incorporating a birefringent crystal between the lens array and the photonic chip interface, which allows for smaller polarization beam offsets and reduces mechanical stress by using a symmetric sandwich structure with matching thermal expansion coefficients, along with high-reflective coatings and block prisms to maintain alignment and reduce optical losses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional optic multiplexing/demultiplexing devices are used, then optical signal transmission is achieved, but mechanical stability deteriorates under harsh environmental conditions due to susceptibility to outside forces and vibrations
Solution Approach 1:
The patent employs a symmetric sandwich structure combining materials with matching thermal expansion coefficients (e.g., glass spacer and glass filters) to create a composite assembly that resists thermal stress and maintains mechanical stability under temperature variations and environmental harshness
2Measurement precision
If traditional alignment structures are used, then optical signal routing is achieved, but alignment precision deteriorates due to increased beam offsets under environmental variations
Solution Approach 1:
The patent utilizes materials with matched thermal expansion coefficients and a symmetric sandwich geometry to compensate for thermal expansion effects, maintaining precise optical alignment across temperature variations by balancing dimensional changes in opposing directions
3Reliability
If larger form factor devices are used, then mechanical stability is improved, but device size increases leading to higher cost and reduced integration efficiency
Solution Approach 1:
The patent divides the optical assembly into modular functional segments (filter array, lens array, birefringent crystal, spacer) that can be independently optimized and assembled in a compact symmetric configuration, achieving stability without excessive size
4Measurement precision
If complex mechanical structures are used to maintain alignment, then alignment stability is improved, but manufacturing complexity and cost increase
Solution Approach 1:
The symmetric sandwich structure with matched thermal expansion materials creates a self-compensating system that automatically maintains optical alignment through balanced thermal expansion/contraction, eliminating the need for complex active alignment mechanisms or adjustment components
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 enhances mechanical stability and reduces optical losses, enabling smaller form factor and cost-effective integration of optic multiplexers/demultiplexers in telecommunication products by minimizing beam offsets and maintaining precise alignment despite environmental variations.
Implementation Method 1
a birefringent crystal disposed between the lens array and the optical interface
Implementation Method 2
using a symmetric sandwich structure with matching thermal expansion coefficients
Data Source
AI summary
Certain embodiments of the present disclosure are directed towards an optical assembly such as a multiplexers/demultiplexers (MDM). One example optical assembly generally includes: a fiber array configured to provide an optical signal with a plurality of wavelengths; optical wavelength filters configured to separate the plurality of wavelengths into respective optical signals; a lens array configured to receive the respective optical signals from the optical wavelength filters and focus the respective optical signals before reaching an optical interface for a photonic chip; and a birefringent crystal disposed between the lens array and the optical interface.