Pigtailed Diode Laser Module Assembly for Low-Loss Fiber Coupling
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
High power fiber lasers underperform due to significant coupling losses of pump light, particularly in pigtailed diode laser modules, as the beam divergence and asymmetry of extended light sources lead to inefficient coupling into the fiber's core, resulting in poor throughput and overheating.
Innovation Solution
The configuration of a pigtailed diode laser module with a slow axis objective lens (SAOL) positioned beyond its focal length, ensuring the fiber's receiving end is spaced from the lens, allowing the combined beam to diverge significantly and minimizing cross-sectional area beyond the focal plane for lossless coupling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the objective lens is positioned at its focal length to focus the beam, then the beam spot size is minimized at the focal plane, but the beam cross-section becomes excessively large beyond the focal plane causing excessive coupling losses into the fiber core
Solution Approach 1:
Instead of positioning the fiber core at the focal plane where the beam is most concentrated, the patent inverts the conventional approach by positioning the fiber core beyond the focal plane where the beam has naturally diverged to a smaller cross-section, achieving lossless coupling
2Loss of energy
If the beam is highly collimated to maintain parallel propagation, then the beam divergence is minimized, but the beam spot size remains large preventing efficient coupling into the fiber core
Solution Approach 1:
The patent changes the propagation parameter of the beam by allowing it to diverge naturally beyond the focal plane rather than maintaining collimation, transforming the beam from a parallel propagation state to a divergent propagation state where the cross-section matches the fiber core size
3Loss of energy
If the fiber core is positioned at the focal plane to receive the focused beam, then the beam concentration is maximized, but the beam cross-section is still too large causing significant energy loss
Solution Approach 1:
The patent inverts the conventional focusing approach by positioning the fiber core beyond the focal plane where the beam has naturally converged to a smaller cross-section, achieving both high intensity and minimal coupling loss simultaneously
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 substantially lossless coupling of light into the fiber core, reducing losses by 2-3% and preventing overheating, thereby improving efficiency and performance.
Implementation Method 1
at least one slow axis objective lens (SAOL) located downstream from the last downstream reflector and operative to focus the combined beam at least in the slow axis in its focal plane
Implementation Method 2
operative to focus the combined beam at least in the slow axis in its focal plane
Data Source
Figure 1~2
Figure 3~5
Figure 6~7
AI summary
A pigtailed diode laser module is configured with a case housing a plurality of multimode chips which are arranged in at least one row and output respective beams in one direction, Each output beam is collimated in upstream fast and downstream slow axes collimators which are spaced from one another in the one direction. The collimated output beams are incident on respective mirrors redirecting the incident output beams in another direction which is transverse to the one direction. Propagating further one above another, the output beams constitute a combined beam which diverges In the slow axis while propagating towards at least one lens which focuses the combined beam in the slow axis in the focal plane thereof. The output fiber is mounted to the case such that its core end is located coplanar with the smallest cross-section of the focused combined beam spaced downstream from the focal plane at a predetermined distance.