Optical Fiber Package Thermal Management
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Solution Overview
Problem
Current optical fiber component packaging solutions fail to effectively manage high power signals and thermally induced mechanical stresses, leading to reliability issues and potential damage from optical losses and heat generation in fiber laser and amplifier devices.
Innovation Solution
A package design featuring a thermally conductive substrate with a preselected coefficient of thermal expansion and a transparent adhesive bond, optimized to minimize optical absorption and mechanical stress, using materials with high thermal conductivity and transparency to efficiently dissipate heat and manage thermal expansion mismatches.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional packaging materials are used to enclose the optical fiber device, then the device is protected from environmental factors, but thermal expansion mismatches cause mechanical stress and reliability issues at high power levels
Solution Approach 1:
The patent applies parameter changes by carefully selecting the coefficient of thermal expansion (CTE) of the packaging substrate to match that of the optical fiber device. This parameter matching eliminates thermal expansion mismatches that would otherwise cause mechanical stress during temperature cycling, thereby improving device reliability without introducing stress-related failures.
Solution Approach 2:
The patent directly addresses thermal expansion by designing the packaging substrate with a CTE specifically matched to the optical fiber device. This ensures that both materials expand and contract at the same rate during temperature changes, preventing mechanical stress and maintaining bonding integrity between the device and substrate throughout the operational temperature range.
2Temperature
If opaque packaging materials are used to dissipate heat, then thermal management is improved, but optical loss is absorbed and converted to heat that cannot be effectively dissipated
Solution Approach 1:
The patent introduces an optical window as an intermediary component between the optical fiber device and the external environment. This window allows optical losses to escape from the package without being absorbed by the packaging materials, converting what would be trapped heat into escapable radiation. The optical window thus mediates between the need for thermal management and the need to prevent optical energy absorption.
Solution Approach 2:
The patent extracts the harmful optical losses from the packaging system by providing an escape path through the optical window. Instead of allowing optical losses to be absorbed and converted to trapped heat within the opaque packaging materials, the window extracts this energy and allows it to dissipate externally, improving both thermal management and energy efficiency.
3Loss of energy
If transparent adhesive bonds are used to minimize optical absorption, then optical loss is reduced, but mechanical strength and thermal conductivity may be compromised
Solution Approach 1:
The patent employs composite material strategies by selecting adhesive bonds that combine optical transparency with adequate mechanical and thermal properties. The adhesive composition is specifically formulated to maintain transparency in the operational wavelength range while providing sufficient bond strength to secure the device and thermal conductivity to support heat dissipation requirements.
Solution Approach 2:
The patent applies parameter changes by optimizing the adhesive bond's physical and chemical parameters to achieve a balance between transparency, strength, and thermal conductivity. By carefully controlling the adhesive's composition, thickness, and curing characteristics, the patent achieves a material that simultaneously minimizes optical absorption and maintains adequate mechanical bonding strength for high power operation.
4Stability of the object's composition
If the optical fiber device is firmly anchored to the substrate, then mechanical stability is improved, but thermal expansion differences cause stress and potential damage
Solution Approach 1:
The patent resolves this contradiction by matching the CTE of the packaging substrate to that of the optical fiber device. This ensures that both materials expand and contract at the same rate during temperature cycling, eliminating thermal stress even when the device is firmly anchored to the substrate. The mechanical stability is thus maintained without introducing thermal stress damage.
Solution Approach 2:
The patent changes the CTE parameter of the packaging substrate to match the optical fiber device, thereby eliminating the source of thermal stress. This parameter matching allows the device to be firmly anchored for mechanical stability while avoiding the thermal expansion mismatches that would otherwise cause stress and potential damage during temperature variations.
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
The solution effectively reduces temperature elevation and mechanical stress in optical fiber devices, enabling reliable operation at high power levels by controlling heat dissipation and compensating for adhesive bond variations due to temperature changes, thus enhancing the power handling capabilities of optical fiber components.
Implementation Method 1
a thermally conductive packaging substrate (18, 20) surrounding said optical fiber device (12)
Implementation Method 2
the transparency of the adhesive bond (14, 16) is selected in the wavelength band of the signal, said transparency exceeding 80% transmission per mm thickness to minimize optical absorption of optical loss
Implementation Method 3
compensating for any variation in volume of the adhesive bond (14, 16) at each end of the optical fiber device (12) due to external temperature variation and/or to internal temperature variation
Data Source
Figure 1~2
Figure 3a~6b
Figure 4~5
AI summary
A package for an optical fiber device is disclosed. It has a high thermal conductivity packaging substrate surrounding the optical fiber device and has adhesive bonds at each end anchoring the optical fiber device to the substrate. The adhesive bonds are made of a material that has high transparency in damp heat as well as a high glass transition temperature and is capable of withstanding temperatures of over 1000C. The packaging substrate has a high absorption capacity and a CTE in relation to the CTE of the adhesive bond, such as to compensate for any variation in the adhesive bond due to temperature variations. This allows to limit mechanical stress in the optical fiber device within the package.