Optical Module Package Moisture Control for Laser Diode Output
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Solution Overview
Problem
Optical modules with laser diodes emitting at wavelengths below 550 nm experience output degradation due to the dust collection effect, where contaminants from resin curing adhesives adhere to the emission end faces, leading to reduced reliability and increased manufacturing costs.
Innovation Solution
An optical module design with a package moisture content of not more than 3000 ppm, using a resin curing adhesive to bond the multiplexing optical system, and optionally incorporating a moisture absorbent, to prevent output degradation while simplifying the bonding process and reducing costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If resin curing adhesive is used to bond optical components, then ease of manufacture is improved, but contaminants are generated that adhere to laser diode emission end faces causing output degradation
Solution Approach 1:
The patent applies this principle by controlling the package internal environment to have low moisture content (not more than 3000 ppm), which prevents contaminants from the resin curing adhesive from adhering to the laser diode emission end faces. The inert environment (low moisture) eliminates the harmful interaction between adhesive contaminants and the laser diode surface.
Solution Approach 2:
The patent changes the moisture content parameter of the package internal environment to not more than 3000 ppm. This parameter change prevents the dust collection effect by maintaining conditions under which contaminants from the resin curing adhesive do not adhere to the laser diode emission end faces, thus allowing the use of resin curing adhesive while maintaining reliability.
2Reliability
If flux-free solder or adhesive not containing Si-based organic substances is used to bond optical components, then dust collection effect is reduced, but manufacturing complexity and cost increase
Solution Approach 1:
By controlling the package internal moisture content to not more than 3000 ppm, the patent creates an inert environment that prevents contaminants from any type of adhesive (including resin curing adhesive) from adhering to the laser diode emission end faces. This eliminates the need to select specialized adhesives without Si-based organic substances.
Solution Approach 2:
The patent converts the potentially harmful effect of resin curing adhesive contaminants into a beneficial situation by controlling the package moisture content. The low moisture environment prevents the contaminants from causing dust collection, thus allowing the use of conventional resin curing adhesives while maintaining laser diode performance.
3Reliability
If package moisture content is reduced to prevent dust collection, then laser diode reliability is improved, but manufacturing difficulty increases
Solution Approach 1:
The patent sets a specific parameter threshold for package moisture content (not more than 3000 ppm) that prevents dust collection while being achievable through conventional manufacturing processes. This parameter change balances reliability improvement with manufacturing feasibility.
Solution Approach 2:
The patent applies preliminary action by controlling the moisture content during the packaging process before the laser diode is operated. By establishing the low moisture environment (not more than 3000 ppm) in advance, the dust collection effect is prevented from the beginning, avoiding the need for complex post-manufacturing moisture control.
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 output degradation of laser diodes with wavelengths below 550 nm, enhances the reliability of the optical module, and improves productivity by using a resin curing adhesive within the optical module, while maintaining low moisture content to prevent contamination.
Implementation Method 1
a resin curing adhesive is used to bond an optical component to another component
Implementation Method 2
a cap joined to the support for hermetically enclosing the plurality of laser diodes and the multiplexing optical system
Implementation Method 3
a plurality of laser diodes that are hermetically enclosed in a package
Data Source
AI summary
An optical module 1 according to an embodiment includes a plurality of laser diodes (LDs) 21 to 23, a multiplexing optical system 30 combining a plurality of laser beams from the respective plurality of LDs, and a package 10 accommodating the plurality of LDs and the multiplexing optical system. The package includes a support mounted with the multiplexing optical system, and a cap having a transmissive window that allows a resultant light beam to pass through. At least one of the LDs has an oscillation wavelength of nor more than 550 nm. The package has an internal moisture content of not more than 3000 ppm. The multiplexing optical system is fixed to the support by a resin curing adhesive.