Optical Modulator Thermal Management via Housing Grooves
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Solution Overview
Problem
High-frequency optical modulators with LiNbO3 substrates face significant heat generation issues from termination resistors, leading to increased power consumption, size challenges, and reliability concerns, particularly in multilevel modulation formats like DP-QPSK, which deteriorate the optical modulator's performance and transmission devices.
Innovation Solution
The optical modulator design incorporates a housing with features such as grooves, highly heat-conductive materials, thinning of the termination substrate, and level differences between substrate mounting surfaces to effectively redirect and dissipate heat generated from termination resistors, using materials like Cu—W, Cu—Mo, and Al—SiC, and heat-conductive adhesives to manage thermal conduction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If multiple termination resistors are provided on the same termination substrate to reduce the size of the optical modulator, then the device size is reduced, but the heat generation from the termination resistors increases significantly
Solution Approach 1:
The patent divides the termination substrate into multiple independent heat dissipation regions, each equipped with separate heat dissipation holes. This segmentation allows heat from multiple termination resistors to be dissipated independently and efficiently, preventing heat accumulation while maintaining a compact overall structure.
Solution Approach 2:
The patent introduces heat dissipation holes as intermediary structures that facilitate heat transfer from the termination resistors to the external environment. These holes act as thermal conduits, enabling efficient heat dissipation without requiring a larger substrate area, thus resolving the contradiction between compact size and heat management.
2Volume of moving object
If the termination substrate is disposed close to the optical waveguide substrate to meet size reduction requirements, then the device size is reduced, but the heat from the termination substrate deteriorates the temperature drift of the optical modulator
Solution Approach 1:
The patent introduces heat dissipation holes in the termination substrate as intermediary thermal management structures. These holes enable efficient heat dissipation from the termination resistors, preventing heat accumulation that would otherwise cause temperature drift in the optical modulator, while allowing the termination substrate to remain close to the optical waveguide substrate for compactness.
Solution Approach 2:
The patent applies heat dissipation holes specifically in the regions where termination resistors are mounted on the termination substrate. This localized heat dissipation approach targets the heat generation sources directly, preventing thermal interference with the optical waveguide substrate while maintaining the close proximity arrangement for size reduction.
3Speed
If a travelling wave-type electrode constitution is used to operate the optical modulator at high frequency, then the operating frequency is increased, but almost all of the input electrical energy is consumed in the termination resistors and converted to heat
Solution Approach 1:
The patent converts the harmful heat energy generated by the termination resistors into a manageable thermal flow by introducing heat dissipation holes. These holes channel the heat away from sensitive components, transforming the energy loss into a controlled thermal dissipation process that enables high-frequency operation without excessive heat accumulation.
Solution Approach 2:
The patent employs a porous structure in the termination substrate through the heat dissipation holes. This porous configuration increases the surface area available for heat dissipation and facilitates efficient thermal convection, allowing the termination resistors to dissipate the large amount of heat generated during high-frequency operation more effectively.
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 significantly reduces the influence of heat on the optical waveguide substrate, enabling a compact, reliable, and cost-effective optical modulator with suppressed temperature drift, enhancing the stability and performance of optical transmission devices.
Implementation Method 1
a highly heat-conductive material is provided in a part of the housing in which the termination substrate is disposed
Implementation Method 2
in order to suppress conduction of heat generated from the termination resistor to the optical waveguide substrate through the housing, a groove is formed in the housing between the termination substrate and the optical waveguide substrate
Implementation Method 3
heat-conductive adhesives to manage thermal conduction
Data Source
AI summary
To provide a highly-reliable low-cost small optical modulator in which temperature drift is suppressed and an optical transmission device using the same. An optical modulator including an optical waveguide substrate 1 on which an optical waveguide is formed, a signal electrode which is provided on the optical waveguide substrate and applies an electric field to the optical waveguide, a termination substrate 3 provided with a termination resistor that terminates the signal electrode, and a housing 6 in which the optical waveguide substrate and the termination substrate are mounted, in which, in order to suppress conduction of heat generated from the termination resistor to the optical waveguide substrate through the housing, a groove 8 is formed in the housing 6 between the termination substrate 3 and the optical waveguide substrate 1.