Folded Slab Laser Cavity for Efficient Waveguide Mode Coupling
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Folded slab lasers face challenges in efficiently coupling waveguide modes due to natural divergence, leading to reduced coupling efficiency and potential issues with power density distribution, particularly in hybrid waveguide-unstable resonator designs.
Innovation Solution
The design incorporates a resonator cavity with slab waveguides stacked above each other, utilizing cavity folding assemblies with optimized mirror configurations to focus waveguide modes and redirect free-space modes, ensuring efficient coupling of waveguide modes and avoiding power density maxima at fold optics surfaces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If folded slab laser design is used to reduce laser length, then the laser becomes more compact, but waveguide mode coupling efficiency deteriorates due to natural divergence
Solution Approach 1:
The cavity folding assembly is pre-configured with specific curvature radii to provide preliminary focusing action on the radiation beam before it enters the next slab waveguide. This preliminary action counteracts the natural divergence that would otherwise occur during propagation, ensuring that waveguide modes are efficiently coupled into the subsequent slab without requiring post-correction measures.
Solution Approach 2:
The invention changes the optical parameters of the cavity folding assembly by specifying curvature radii for the mirrors that satisfy particular mathematical relationships with the propagation distance. This parameter optimization transforms the folding assembly from a simple directional deflector into an active mode-coupling element that maintains coupling efficiency despite the compact folded geometry.
2Volume of moving object
If compact folded design is implemented, then device size is reduced, but power density distribution becomes problematic with potential burnout risks
Solution Approach 1:
The cavity folding assembly with optimized curvature radii performs preliminary shaping of the radiation beam profile before the beam propagates to subsequent optical elements. This preliminary action distributes power density more uniformly across the beam cross-section, preventing the formation of localized maxima that could cause burnout on fold optics surfaces or waveguide ends.
Solution Approach 2:
The invention applies preliminary anti-action by using the curved mirrors in the cavity folding assembly to counteract the natural tendency of the beam to form high power density concentrations. The specific curvature radii are chosen to pre-compensate for divergent effects and prevent the harmful concentration of power that would otherwise occur in the compact folded geometry.
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 enhances coupling efficiency of waveguide modes, reduces divergence, and prevents power density-related issues, leading to improved laser performance and reduced risk of burnout in folded slab laser designs.
Implementation Method 1
the or each cavity folding assembly is configured to focus the radiation beam emitted from one of the slab waveguides by an amount selected to couple at least one of the waveguide modes into the other of the slab waveguides
Implementation Method 2
each slab waveguide has a thickness sized to support at least one waveguide mode vertically in the slab waveguide and a width sized to support free space modes horizontally across the slab waveguide
Implementation Method 3
at least one cavity folding assembly configured to direct a radiation beam emitted from one of the slab waveguides into another of the slab waveguides
Data Source
AI summary
A folded slab waveguide laser having a hybrid waveguide-unstable resonator cavity. Multiple slab waveguides of thickness âtâ supporting vertical waveguide modes are physically arranged above one another in a stack and optically arranged in series through one or more cavity folding assemblies with curved mirrors. A gain medium such as a gas is arranged in each slab. Each cavity folding assembly is designed to redirect the radiation beam emitted from one slab waveguide into the next waveguide and also at the same time to provide a focus for the radiation beam so that a selected vertical waveguide mode (or modes) is (or are) coupled efficiently into the next slab.