Fiber Laser Pumping Unit Elliptical Chamber Design
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Solution Overview
Problem
Fiber lasers face inefficiencies when pump light is irradiated vertically, and inter-fiber coupling is often required, leading to suboptimal performance and beam quality issues, particularly with multimode fibers.
Innovation Solution
The excitation unit design includes a longitudinal or transverse pump light source with adjustable imaging optics and a seed laser, where the excitation fiber is arranged in alternating curves and housed in elliptically shaped excitation chambers with reflective surfaces, allowing direct coupling of pump light into the fiber without additional fibers, enhancing beam quality and power distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If pump light is irradiated vertically into the fiber, then coupling efficiency is improved, but beam quality deteriorates due to mode mixing in multimode fibers
Solution Approach 1:
The pump light source is segmented into multiple individual laser diodes arranged in a specific geometric pattern around the fiber, rather than using a single vertical source. This segmentation allows each diode to pump a specific region of the fiber core, maintaining beam quality while achieving high coupling efficiency through distributed pumping.
Solution Approach 2:
The pumping approach transitions from vertical (one-dimensional) irradiation into the fiber end face to a lateral (two-dimensional) arrangement where multiple diodes surround the fiber. This dimensional change enables spatial distribution of pump light while preserving mode quality through careful geometric positioning.
2Power
If inter-fiber coupling is used to combine pump light, then pumping capability is improved, but device complexity increases
Solution Approach 1:
Multiple individual laser diodes are merged into a single integrated pump module that directly surrounds the fiber. This combining approach achieves high pumping capability through multiple light sources while avoiding the complexity of inter-fiber coupling by integrating all diodes into one modular unit with common mounting and control.
Solution Approach 2:
A common reflective cavity or housing serves as an intermediary structure that holds multiple laser diodes and directs their light toward the fiber. This mediator enables coordinated pumping from multiple diodes without requiring complex fiber-to-fiber coupling mechanisms.
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 achieves efficient and stable laser beam generation with improved beam quality and power distribution, enabling high-power output and efficient parallel pumping of multimode fibers, even with larger core diameters, while eliminating the need for inter-fiber coupling.
Implementation Method 1
housed in elliptically shaped excitation chambers with reflective surfaces
Implementation Method 2
adjustable imaging optics
Implementation Method 3
longitudinal or transverse pump light source with adjustable imaging optics and a seed laser
Implementation Method 4
Fiber lasers are pumped optically by coupling radiation, for example from diode lasers
Data Source
Figure 1
Figure 2~3
Figure 4
AI summary
The invention relates to an excitation unit (2) for a fiber laser, said excitation unit having an excitation fiber (3) and a longitudinal axis (6) and forming a two-dimensional or three-dimensional structure in a resonator region of the fiber laser. When viewed in cross-section, the excitation fiber (3) consists of an active fiber core (3a), a pump cladding (3b) that surrounds the active core (3a), a quartz glass casing (3) that surrounds the pump cladding (3b), and at least one cover (3e). The resonator region is equipped with a base plate (5) on which a plurality of excitation housings (18) are formed, each excitation housing delimiting a gas-tight excitation chamber (22). The excitation fiber runs through each excitation chamber at least once and is held in holding units (8) laterally to each excitation chamber when viewed in the longitudinal direction (6) of the excitation fiber. The cover of the excitation fiber is removed in some regions in the excitation chambers and is completely present in the regions of the holding units (8). The excitation chambers (22) are formed in an elliptical manner in a cross-section perpendicular to the longitudinal axis of the excitation fiber. The excitation housings (18) are provided with a translucent window (19), and a transversal pump light source (30) is arranged in the region of each translucent window (19) such that a pump light (25) that leaves the pump light source (30) impinges onto the longitudinal axis of the excitation fiber preferably in a perpendicular manner.