Co-doped Laser Gain Medium Parasitic Suppression
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional methods for suppressing parasitics in optical devices, such as laser devices, face challenges including increased scattering loss, high thermal expansion coefficients of optical adhesives, and inefficiencies in absorbing lasing wavelengths, leading to persistent parasitic issues.
Innovation Solution
The use of a core region doped with sensitizer ions that absorb pumping wavelengths and transfer energy to laser active ions, combined with a cladding region doped with laser active ions transparent to pumping wavelengths but capable of absorbing transverse lasing wavelengths, ensures direct contact and effective suppression of parasitics by bonding these regions together.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If an E-wave coating is applied on the gain medium to limit NA and suppress parasitics, then parasitic suppression is improved, but device complexity and manufacturing cost increase due to additional surface treatment processes
Solution Approach 1:
The patent extracts the parasitic suppression function from the external E-wave coating and surface treatment processes, and integrates it directly into the gain medium through co-doping with sensitizer ions (e.g., Yb³⁺) and laser active ions (e.g., Er³⁺). The sensitizer ions absorb pump energy and transfer it to laser active ions, while the laser active ions absorb parasitic lasing wavelengths within the gain medium itself, eliminating the need for separate E-wave coatings and surface roughening treatments.
Solution Approach 2:
The patent merges multiple functions into a single co-doped gain medium: (1) pump energy absorption by sensitizer ions, (2) energy transfer to laser active ions, (3) laser emission at desired wavelengths, and (4) parasitic suppression through absorption of transverse lasing wavelengths by laser active ions. This consolidation eliminates the need for separate E-wave coatings, surface treatments, and adhesives, reducing device complexity while maintaining parasitic suppression effectiveness.
2Object-affected harmful factors
If the gain medium surface is roughened to suppress parasitics, then parasitic suppression is improved, but pump energy efficiency deteriorates due to increased scattering loss of guided pump light
Solution Approach 1:
The patent applies local quality by creating spatially differentiated ion distributions within the gain medium. Sensitizer ions are concentrated in regions where pump absorption is needed, while laser active ions are distributed to provide both lasing action and parasitic suppression. This localized functional distribution allows parasitic suppression without requiring global surface roughening that would scatter pump light and reduce efficiency.
3Ease of manufacture
If optical adhesive is used to secure gain medium to heat-sink, then mechanical bonding is achieved, but alignment stability deteriorates due to high coefficient of thermal expansion
Solution Approach 1:
The patent extracts the bonding function from optical adhesives and replaces it with direct mechanical bonding between the co-doped gain medium and heat-sink substrates. This eliminates the adhesive layer that causes thermal expansion mismatches and alignment instability, while maintaining effective thermal coupling through direct contact bonding interfaces.
4Object-affected harmful factors
If sensitizer ions are used in cladding region to absorb lasing wavelength, then parasitic absorption is improved, but pump energy efficiency deteriorates due to absorption spectrum mismatch with emission spectrum
Solution Approach 1:
Instead of placing sensitizer ions in the cladding region (conventional approach), the patent inverts the approach by placing laser active ions in the cladding region and keeping the core region as the primary gain medium. The laser active ions in the cladding absorb parasitic lasing wavelengths that escape from the core, while the sensitizer ions remain confined to the core region where they efficiently absorb pump energy and transfer it to laser active ions, maintaining spectral matching and pump efficiency.
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 approach reduces parasitic losses by absorbing transverse lasing wavelengths in the cladding region, maintaining pump energy efficiency and alignment stability across varying temperatures, while eliminating the need for additional surface treatments and adhesives, thus enhancing the overall performance and cost-effectiveness of the optical device.
Implementation Method 1
comprising a plurality of a first type of ions configured to absorb energy at a pumping wavelength and to transfer the absorbed energy to a plurality of a second type of ions configured to lase at a lasing wavelength after receiving the transferred energy
Implementation Method 2
comprising another plurality of the second type of ions that are configured to suppress parasitics in the optical device by absorbing energy of at least a transverse portion of the lasing wavelength that enters the cladding region
Implementation Method 3
a plurality of a second type of ions configured to lase at a lasing wavelength after receiving the transferred energy
Data Source
Figure 1
Figure 2
Figure 3
AI summary
An optical device, a method of making a laser gain medium, and a method of suppressing parasitics in a laser device include a core region (110) comprising a plurality of a first type of ions, e.g. ytterbium, that absorb energy at a first wavelength and transfer the absorbed energy to a plurality of a second type of ions, e.g. erbium, that lase at a second wavelength after receiving the transferred energy. A cladding region (108a,108b) coupled to the core region comprising another plurality of the second type of ions that suppress parasitics in the optical device by absorbing energy of at least a transverse portion of the second wavelength that enters the cladding region.