Bidirectionally Tapered Cladding Light Stripper for High-NA Leakage

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Solution Overview

Problem

Current cladding light strippers are unable to reliably remove cladding light associated with numerical apertures (NAs) greater than a specific NA, leading to leakage and overheating of polymeric coatings in high-power lasers, which results in performance degradation and failure.

Innovation Solution

A selective NA cladding light stripper is designed with a bidirectionally tapered exterior cladding and a light removal component, where the taper ratios of the cladding sections are matched to the NA of the light removal component, allowing for the targeted removal of cladding light with NAs greater than the maximum selected NA, thereby preventing leakage and overheating.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a conventional cladding light stripper is used, then light removal is achieved, but it cannot reliably remove cladding light with NAs greater than a specific NA, leading to leakage and overheating

Engineering Contradiction:

Improvereliability of cladding light removalVSAvoidability to handle different NA ranges

Core Design Contradiction:

ReliabilityVSAdaptability or versatility

Solution Approach 1:

The exterior cladding is divided into different sections with different taper ratios: a first section with a first taper ratio, a second section with a second taper ratio, and a central section with no taper. Each section is optimized to handle specific NA ranges of cladding light, with the first section addressing lower NAs and the second section addressing higher NAs, thereby achieving reliable removal across the full NA spectrum

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent changes the geometric parameters of the exterior cladding by introducing bidirectional tapering with different taper ratios in different sections. This parameter modification allows the numerical aperture of each cladding section to be tailored to specific NA ranges, enabling the light stripper to effectively remove cladding light with NAs greater than previously achievable while preventing leakage and overheating

Inventive Principle:

Principle #35Parameter changes

2Reliability

If the exterior cladding is bidirectionally tapered with matched taper ratios, then selective removal of high-NA cladding light is achieved, but the device complexity increases

Engineering Contradiction:

Improveselectivity of light removalVSAvoidstructural complexity of cladding sections

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The exterior cladding is segmented into three distinct sections along the optical fiber length: a first section with a first bidirectional taper, a central section with no taper, and a second section with a second bidirectional taper. This segmentation allows each section to be independently optimized for specific functions, achieving selective removal of high-NA cladding light while maintaining a manageable structural complexity through systematic division

Inventive Principle:

Principle #1Segmentation

3Reliability

If cladding light with high NA is not removed, then light propagation is maintained, but leakage occurs causing overheating and performance degradation

Engineering Contradiction:

Improveperformance reliability of optical fiberVSAvoidoverheating and leakage effects

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent converts the potentially harmful high-NA cladding light into a beneficial effect by using the bidirectional tapering to transform the propagation characteristics of this light. The taper sections modify the mode field distribution, causing high-NA cladding light to be selectively removed through controlled leakage into the surrounding medium, thereby preventing harmful overheating while utilizing the light's energy in a controlled manner

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

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 effectively reduces the likelihood of high-power cladding light leakage, improving the performance and reliability of optical fibers and lasers by ensuring that only cladding light with NAs less than or equal to the selected NA is propagated, thus minimizing the risk of overheating and failure.

Implementation Method 1

The intermediate portion is bidirectionally tapered, and the light removal component is disposed on one or more regions of a central section of the intermediate portion

Methodology Applied

Scientific EffectTapering: Geometry

Implementation Method 2

a light removal component, wherein: the exterior cladding of the optical fiber circumferentially surrounds the core of the optical fiber

Methodology Applied

Scientific EffectLight absorption: Absorption (EM radiation)

Data Source

PatentUS20250004195A1Selective numerical aperture cladding light stripper

Publication Date: 2025.01.02 WELLS FARGO BANK NA

AI summary

In some implementations, a cladding light stripper includes an optical fiber that includes a core and an exterior cladding, and a light removal component. The exterior cladding of the optical fiber circumferentially surrounds the core of the optical fiber. The exterior cladding includes a first portion, a second portion, and an intermediate portion disposed between the first portion and the second portion. The intermediate portion is bidirectionally tapered. The light removal component is disposed on one or more regions of a central section of the intermediate portion.