Glass Block Cladding Light Extraction for High-Power Fiber Lasers
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Solution Overview
Problem
High-power optical systems, such as fiber lasers and amplifiers, face issues with unwanted cladding light causing overheating due to residual pump power and reduced spectral purity, which affects multiplexing and thermal management.
Innovation Solution
An optical fiber is embedded in a glass block with a refractive index greater than the cladding, surrounded by a fluid with a matching refractive index, and housed in a metal block with high thermal conductivity to efficiently extract and absorb unwanted cladding light, minimizing heat generation and absorption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If high power levels are employed in fiber lasers and optical amplifiers, then the optical output power is improved, but unwanted cladding light causes overheating and thermal management issues
Solution Approach 1:
The patent extracts unwanted cladding light from the optical fiber by embedding it in a glass block with higher refractive index, causing total internal reflection at the cladding-glass interface. This removes the harmful cladding modes that would otherwise cause overheating, while preserving the core light transmission.
Solution Approach 2:
The glass block acts as an intermediary medium between the optical fiber and the external environment. By positioning the fiber within the glass block and utilizing the refractive index difference, the system mediates the extraction of cladding light without directly contacting the fiber, thereby preventing overheating while maintaining high power transmission.
2Temperature
If cladding light is removed using conventional methods, then thermal management is improved, but spectral purity and multiplexing capability deteriorate
Solution Approach 1:
The patent applies local quality by creating different optical environments for the core and cladding modes. The glass block selectively interacts with cladding light through total internal reflection at the cladding-glass interface, while the core light remains unaffected. This localized differentiation allows thermal management improvement without compromising spectral purity.
3Object-generated harmful factors
If a glass block with higher refractive index is used to remove cladding light, then unwanted light extraction is improved, but device complexity increases
Solution Approach 1:
The patent merges the light extraction function with a simple glass block structure, combining multiple functions (refractive index mismatch for light extraction, mechanical support, and thermal management) into a single component. This eliminates the need for complex cladding mode strippers or multiple separate elements, thereby reducing device complexity while effectively removing unwanted cladding light.
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
Effectively removes unwanted cladding light, reducing thermal flux and preserving spectral purity, enabling operation in high-power systems up to the megawatt range with controlled temperature and efficient heat extraction.
Implementation Method 1
The glass block and the metal housing, in combination, remove unwanted cladding light
Implementation Method 2
a glass block with a refractive index that is greater than or equal to a refractive index of a fiber cladding
Implementation Method 3
a metal housing that is located external to the glass block
Data Source
Figure 1
Figure 2A~2B
AI summary
The present disclosure is directed to removing unabsorbed cladding light in high-power optical systems. Some embodiments comprise a glass block with a refractive index that is greater than a refractive index of a fiber cladding, and a metal housing that is located external to the glass block. The glass block and the metal housing, in combination, removes excess light.