Integrated Optical Module Assembly for Stable Waveguide Coupling
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Solution Overview
Problem
Existing optical devices face challenges in miniaturization due to large components and free space optical systems, and hybrid integrated optical modules experience reliability issues with temperature dependence and bonding strength due to UV-curable adhesives, leading to instability in laser beam output and potential slip-off of optical semiconductor elements during wire-bonding.
Innovation Solution
An integrated optical device with a mounting base, optical semiconductor device, and substrate where the optical semiconductor device is connected through a metal layer, and the mounting base is connected to the substrate through another metal layer, with both bases having their bottom surfaces on the same plane, and an antireflection film is provided between the semiconductor device and waveguide, enhancing bonding strength and heat dissipation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a free space optical system using mirrors and lenses is used to integrate optical elements, then optical functions can be achieved, but the device size becomes large and miniaturization is limited
Solution Approach 1:
The patent replaces the free space optical system (mechanical system using mirrors and lenses) with an integrated optical waveguide system. Light is guided through dielectric waveguides formed on a substrate, eliminating the need for bulky mechanical optical components and enabling miniaturization while maintaining optical functionality.
Solution Approach 2:
The patent merges multiple optical elements (light source, waveguides, optical semiconductor devices) into a single integrated structure on a substrate. The dielectric waveguides are formed directly on the substrate, and optical semiconductor devices are mounted on the same substrate, combining previously separate components into one compact unit.
2Ease of manufacture
If UV-curable adhesive is used to bond semiconductor chip and PLC chip, then bonding can be achieved, but bonding strength is insufficient and components may slip off during wire-bonding
Solution Approach 1:
The patent changes the bonding method from chemical bonding (UV-curable adhesive) to physical bonding (soldering). The soldering process uses molten solder material that solidifies to form strong mechanical bonds, significantly increasing bonding strength while maintaining ease of manufacture through standardized soldering processes.
Solution Approach 2:
The patent uses a composite bonding approach where solder material (metal alloy) is used instead of pure organic adhesive. The solder forms a composite joint between the semiconductor chip and substrate that combines mechanical strength with thermal conductivity, addressing both bonding strength and heat dissipation requirements.
3Ease of manufacture
If UV-curable adhesive is used for bonding, then assembly can be performed, but temperature dependence causes expansion and contraction leading to alignment accuracy degradation
Solution Approach 1:
The patent changes the bonding material properties from polymer-based (UV adhesive) to metal-based (solder). Solder has much lower thermal expansion coefficients similar to the substrate and chip materials, reducing thermal expansion and contraction during temperature changes, thereby maintaining alignment accuracy while allowing standard assembly processes.
4Adaptability or versatility
If optical semiconductor device is mounted on substrate, then integration is achieved, but heat dissipation is insufficient causing operational instability
Solution Approach 1:
The patent uses solder material as a composite thermal management solution. The solder joint serves dual purposes: mechanical bonding and thermal conduction. The metal solder has high thermal conductivity, creating an efficient heat dissipation path from the optical semiconductor device to the substrate, stabilizing operating temperature while maintaining integration.
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 provides improved heat dissipation and maintains operational stability across temperature changes, preventing slip-off of semiconductor elements and ensuring reliable laser beam output, thus enhancing the reliability and miniaturization of optical devices.
Implementation Method 1
the optical semiconductor device is connected to the mounting base through a metal layer
Implementation Method 2
an antireflection film is provided between the semiconductor device and waveguide
Data Source
AI summary
An integrated optical device includes: a mounting base; an optical semiconductor device which is provided on a surface of the mounting base; a substrate; and an optical waveguide which is provided on a surface of the substrate, wherein an incident surface of the optical waveguide is disposed to face an emission surface of the optical semiconductor device, wherein light emitted from the optical semiconductor device is able to be incident to the optical waveguide, wherein the optical semiconductor device is connected to the mounting base through a metal layer, wherein the mounting base is connected to the substrate through the other metal layer, and wherein a mounting base bottom surface on the side opposite to a surface of the mounting base and a substrate bottom surface on the side opposite to a surface of the substrate are provided on the substantially same plane.