TIR Fiber Optic Interface Module Passive Alignment
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Solution Overview
Problem
Fiber optic interface modules for consumer electronics require high data rate compatibility with forgiving misalignment tolerances and a passive alignment process to efficiently couple light between low-cost, low-power light sources and optical fibers, while maintaining manufacturing simplicity.
Innovation Solution
A fiber optic interface module with a monolithic body featuring total-internal-reflection (TIR) mirrors, integral lens surfaces, and passive alignment features that support optical fibers and active photo-devices, allowing for efficient optical communication with tolerance to lateral misalignment and reduced manufacturing complexity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If traditional alignment methods are used to couple light from VCSELs to optical fibers, then coupling efficiency can be achieved, but manufacturing complexity and cost increase due to requiring precise active alignment processes
Solution Approach 1:
The module employs self-aligning features where the VCSEL, lens, and optical fiber are mechanically coupled through integrated structures that automatically establish proper optical alignment. The lens is positioned at a predetermined distance from the VCSEL through mechanical constraints in the module housing, and the optical fiber is aligned to the lens axis through keyed features, eliminating the need for external active alignment equipment and procedures.
Solution Approach 2:
The patent integrates multiple components into a unified structure where the VCSEL mount, lens holder, and fiber positioning features are combined into a single self-aligning assembly. This merging of alignment functions into the module structure itself ensures that proper optical coupling is achieved through the inherent mechanical design rather than through separate alignment steps.
2Ease of manufacture
If passive alignment is implemented to simplify manufacturing, then manufacturing cost and time are reduced, but achieving high coupling efficiency becomes more difficult
Solution Approach 1:
The module design incorporates pre-established mechanical relationships between components during the manufacturing process. The lens is pre-positioned at a specific distance from the VCSEL through molded features, and the optical fiber is pre-aligned to the lens axis through keyed mounting structures. These preliminary mechanical arrangements ensure that optimal optical coupling is achieved without requiring post-assembly active alignment adjustments.
Solution Approach 2:
The patent optimizes specific geometric parameters of the alignment features, including the lens-to-VCSEL distance, the numerical aperture matching between lens and fiber, and the angular orientation of mounting surfaces. By carefully selecting and controlling these dimensional parameters during manufacturing, the design achieves high coupling efficiency through passive alignment alone.
3Volume of moving object
If compact module size is reduced for consumer electronics applications, then space requirements are minimized, but thermal management and optical performance become more challenging
Solution Approach 1:
The module employs a nested arrangement where the optical components (VCSEL, lens, fiber) are positioned in a compact axial sequence within a small cylindrical housing. The lens is nested between the VCSEL and the optical fiber connector, allowing the entire optical path to be contained within a minimal volume while maintaining proper component spacing for thermal and optical performance.
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 achieves high coupling efficiency and tolerance to lateral misalignment, reducing manufacturing costs and time while maintaining optimal performance for high-data-rate applications in consumer electronics.
Implementation Method 1
a ridge formed in the top surface and having an angled wall that defines a total-internal-reflection (TIR) mirror
Data Source
AI summary
A fiber optic interface module and assemblies using same are disclosed, wherein the modules have at least one lens that defines a folded optical path through the module body. The module operably supports one or more optical fibers adjacent an end wall. The module includes one or more lenses formed therein for coupling light from one or more light sources to the corresponding one or more optical fibers. The one or more lenses each have a folded optical path formed by total internal reflection within the module body. The one or more lenses each include a lens surface configured to define a back focus that resides within a corresponding one of the optical fibers.