External Cavity Laser Thermal Stabilization via Decoupled Intermediate Plate
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Solution Overview
Problem
External-cavity tuneable lasers in WDM systems face challenges in maintaining wavelength stability due to mechanical deformations caused by thermal fluctuations, leading to optical misalignments and frequency shifts, which affect output power and accuracy, especially at narrower channel spacings and varying temperatures.
Innovation Solution
The solution involves thermally coupling the gain medium and end mirror to a thermoelectric cooler (TEC) with a reduced surface area and mechanically decoupling the optical bench from the TEC's upper carrier plate using an intermediate plate, ensuring thermal stabilization while minimizing mechanical deformations, thus maintaining optical path length stability without active thermal control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the gain medium and end mirror are thermally coupled to a TEC with large surface area, then thermal stabilization is improved, but mechanical deformations increase causing optical misalignment
Solution Approach 1:
The patent divides the thermal management system into two distinct functional zones: a large surface area TEC for thermal stabilization and a small surface area intermediate plate for mechanical support. This segmentation allows the TEC to provide comprehensive thermal coverage without transmitting excessive mechanical deformations to the optical components.
Solution Approach 2:
The patent introduces an intermediate plate as a mediator between the TEC and the optical bench. This intermediate plate with reduced surface area acts as a mechanical buffer that blocks deformation transmission while maintaining thermal coupling, thereby resolving the contradiction between thermal stabilization and mechanical stability.
2Temperature
If the optical bench is directly coupled to the TEC, then thermal control is improved, but optical path length stability deteriorates due to mechanical deformations
Solution Approach 1:
The intermediate plate serves as a mediator that decouples the mechanical connection between the TEC and optical bench while preserving thermal connection. Its reduced surface area minimizes deformation transmission to the optical path, thereby maintaining optical path length stability during thermal control operations.
Solution Approach 2:
The patent applies local quality by creating a thermal coupling zone with large surface area contact between the intermediate plate and TEC, while maintaining a small surface area contact between the intermediate plate and optical bench. This localized differentiation optimizes both thermal transfer and mechanical stability in their respective zones.
3Stability of the object's composition
If TEC surface area is reduced, then mechanical deformations are minimized, but thermal stabilization effectiveness decreases
Solution Approach 1:
The patent segments the surface area function between two components: the TEC has large surface area for effective thermal stabilization, while the intermediate plate has small surface area for minimizing mechanical deformations. This functional segmentation allows each component to be optimized for its primary purpose.
Solution Approach 2:
The intermediate plate acts as an intermediary that receives thermal energy from the large-surface-area TEC and transfers it to the optical components, while its small surface area limits mechanical deformation generation and transmission, thereby resolving the trade-off between thermal effectiveness and mechanical stability.
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 passively compensates for optical path length variations, reducing the need for large injection current adjustments and maintaining stable output power and frequency, with injection current variations within ±5 mA, thereby enhancing the stability of the lasing signal across a wide temperature range.
Implementation Method 1
a gain medium, which is in thermal coupling to a thermoelectric cooler (TEC). Preferably, an end mirror of the laser assembly is in thermal coupling to the thermoelectric cooler
Implementation Method 2
a thermoelectric cooler (TEC)
Implementation Method 3
mechanically decoupling the optical bench from the TEC's upper carrier plate using an intermediate plate, ensuring thermal stabilization while minimizing mechanical deformations
Data Source
AI summary
The present invention relates to an external-cavity laser module comprising a thermoelectric cooler (TEC) including an upper carrier plate having an upper surface, said TEC being configured to stabilize the temperature of the upper surface at a substantially constant temperature. The laser module further comprises a laser assembly mounted on an optical bench, which is in thermal coupling with said upper surface, said laser assembly comprising a gain medium for emitting an optical beam into the external cavity and an end mirror.