Monolithic Optical Coupling Module Using Total Internal Reflection
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Solution Overview
Problem
Conventional optical devices for VCSELs are complex and costly due to the need for multiple components, and they struggle with adjusting light splitting ratios, which are often polarization-sensitive.
Innovation Solution
A monolithic optical coupling module using two contiguous total internal reflection (TIR) surfaces simplifies assembly, reduces components, and allows for arbitrary light splitting ratios by predetermining the splitting ratio based on physical features of the TIR surfaces, eliminating polarization sensitivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a tilted glass reflective mirror is used to reflect light to a monitor photodetector, then the light reflection function is achieved, but the assembly becomes complex and expensive with multiple components
Solution Approach 1:
The patent merges the light reflection function and the structural support into a single monolithic optical module. The module integrates a light source, optical coupling elements, and a monitor photodetector assembly into one unified structure, eliminating the need for separate tilted glass reflective mirrors and multiple discrete components. This integration directly reduces assembly complexity while maintaining the light reflection function through internal optical paths.
Solution Approach 2:
The monolithic optical module serves multiple functions simultaneously: it provides structural support, guides light propagation, performs optical coupling, and directs light to the monitor photodetector. The housing structure itself is designed to define optical paths and contain all necessary components, making the assembly universal and eliminating the need for separate specialized components for each function.
2Reliability
If a tilted glass reflective mirror is used for light splitting, then the splitting function is achieved, but the assembly cost increases due to multiple components
Solution Approach 1:
The light splitting function is integrated into the monolithic module structure itself. The housing and internal surfaces are designed to perform beam splitting and direction without requiring separate glass mirrors or complex optical assemblies. This integration reduces the number of bill of materials items and eliminates costly assembly steps associated with aligning and securing multiple optical components.
3Device complexity
If an air-gap in polymer is used for light splitting, then the assembly is simplified, but the splitting ratio cannot be easily adjusted and becomes polarization-sensitive
Solution Approach 1:
The patent employs parameter changes in the form of microlens arrays with varying focal lengths, curvatures, and positions to control the light splitting ratio. By adjusting the optical parameters of the microlens array during manufacturing or through selectable configurations, the splitting ratio can be precisely controlled without changing the basic monolithic structure. This approach maintains assembly simplicity while providing the needed adaptability.
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 reduces assembly complexity and cost while enabling precise control over light splitting ratios, making it suitable for various applications without polarization-dependent loss.
Implementation Method 1
A first optical beam entering the monolithic optical module through the first optical port and incident on the first internal optical beam dividing interface may be partially reflected by the first TIR surface to travel in a first direction as a second optical beam and partially reflected by the second TIR surface to travel in a second direction as a third optical beam
Data Source
AI summary
In one aspect, an optical device comprises a monolithic optical module which includes a first total internal reflection (TIR) surface, a second TIR surface adjacent the first TIR surface, and a first optical port aligned with the first internal optical beam dividing interface. An interface between the first TIR surface and the second TIR surface forms a first internal optical beam dividing interface. An exterior surface of the first TIR surface and an exterior surface of the second TIR surface form a generally V-shaped notch on the monolithic optical module. A first optical beam entering the monolithic optical module through the first optical port and incident on the first internal optical beam dividing interface is partially reflected by the first TIR surface to travel in a first direction as a second optical beam and partially reflected by the second TIR surface to travel in a second direction as a third optical beam. The second direction is generally opposite to the first direction.