Optical Fiber End Piece Reflection for Input Coupling Evaluation
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Solution Overview
Problem
Existing methods for evaluating input coupling quality in optical fiber units are inadequate, leading to difficulties in achieving optimal beam quality and high losses due to the formation of power plateaus and the inability to accurately assess input coupling quality, especially when using fiber cladding light.
Innovation Solution
Incorporating a reflection element in the optical fiber unit to divert a portion of useful light away from the propagation direction, allowing for reproducible and stable evaluation of input coupling quality by capturing back-reflections, which avoids power plateaus and ensures consistent beam quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If leakage light is captured to monitor input coupling quality, then monitoring capability is provided, but a power plateau forms causing high power measurement even when beam quality is poor
Solution Approach 1:
The patent extracts only the useful light component from the total light by using a spatial filter (iris diaphragm) that blocks cladding light and leakage light, allowing accurate measurement of only the coupled beam power without the masking effect of power plateaus
Solution Approach 2:
The patent introduces an intermediary spatial filter (iris diaphragm) between the optical fiber and detector that mediates the measurement process by selectively transmitting only the useful light while blocking other light components that cause measurement errors
2Measurement precision
If cladding light is captured to evaluate input coupling quality, then evaluation capability is provided, but optimum evaluation is not achieved and it is only appropriate for higher modes
Solution Approach 1:
Instead of measuring cladding light (what is excluded from the core), the patent inverts the approach by directly measuring the useful light in the core through spatial filtering, making the measurement applicable to all modes without restriction
Solution Approach 2:
The patent changes the measurement parameter from cladding light intensity to spatially-filtered useful light intensity, which fundamentally alters the measurement characteristics to provide accurate coupling quality evaluation for all beam modes
3Reliability
If laser light is coupled into the optical fiber unit, then light guiding function is achieved, but input coupling quality is difficult to assess and monitor
Solution Approach 1:
The patent implements a feedback measurement system where the detected useful light power is used to assess and monitor input coupling quality in real-time, enabling continuous optimization of the coupling process
Solution Approach 2:
The patent makes the optical fiber unit self-diagnosing by incorporating the spatial filter and detector directly into the fiber assembly, allowing the system to self-monitor its coupling quality without external complex equipment
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
Enables precise and stable evaluation of input coupling quality, facilitating optimal alignment and power regulation, while minimizing power losses and enabling process monitoring.
Implementation Method 1
The first end piece includes a reflection element configured to divert a portion of useful light propagating along a direction of propagation through the light guiding region away from the direction of propagation
Data Source
AI summary
An optical fiber unit includes an optical fiber. The optical fiber includes a light guiding region configured for guiding light through the optical fiber, an input coupling end having a first fiber end surface for coupling the light into the light guiding region, and an output coupling end having a second fiber end surface for coupling the light out of the light guiding region. The optical fiber unit further includes a first end piece arranged at one of the input coupling end and the output coupling end. The first end piece is configured to couple the light into the light guiding region or couple the light out of the light guiding region. The first end piece includes a reflection element configured to divert a portion of the light propagating along a direction of propagation through the light guiding region away from the direction of propagation.