Monolithic Optical Coupling Module Using Total Internal Reflection Surfaces
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Solution Overview
Problem
Conventional VCSEL assemblies are complex and costly due to the need for multiple components, and existing monolithic optical modules suffer from polarization-sensitive light splitting ratios that cannot be easily adjusted.
Innovation Solution
A monolithic optical coupling module utilizing total internal reflection (TIR) surfaces with adjustable splitting ratios, where the shape and orientation of TIR surfaces determine the beam splitting ratio, eliminating the need for additional components and reducing assembly complexity.
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 integrates the light reflection function directly into the monolithic optical module substrate by forming TIR surfaces as integral parts of the polymer structure. This eliminates the need for separate tilted glass reflective mirrors and reduces the assembly to a single monolithic component, thereby reducing complexity while maintaining the light reflection function.
Solution Approach 2:
The invention extracts the light reflection function from the separate tilted glass mirror component and transfers it to the monolithic optical module itself through TIR surfaces. This separation of the reflection function from external components simplifies the overall assembly structure.
2Ease of manufacture
If an air-gap in polymer is used for light splitting, then the assembly process is simplified, but the splitting ratio cannot be easily adjusted and is polarization-sensitive
Solution Approach 1:
The patent enables adjustment of the splitting ratio by changing the geometric parameters of the TIR surfaces, specifically the angle θ and the width w of the notch. These parameter changes allow arbitrary splitting ratios to be achieved while maintaining polarization insensitivity, as the TIR mechanism does not differentiate between TE and TM polarizations.
Solution Approach 2:
The invention introduces asymmetry in the form of a V-shaped notch with specific angular orientation (θ) to achieve polarization-insensitive light splitting. The asymmetric geometry of the TIR surfaces allows control over the splitting ratio while maintaining equal reflectivity for both TE and TM polarizations, unlike symmetric air-gap designs.
3Reliability
If multiple components are used in VCSEL assembly, then the light splitting and reflection functions can be achieved, but the cost increases
Solution Approach 1:
The patent combines multiple optical functions (light splitting, light reflection, and polarization insensitivity) into a single monolithic optical module. This integration eliminates the need for multiple separate components such as tilted mirrors, beam splitters, and alignment mechanisms, thereby reducing manufacturing cost while maintaining optical performance.
Solution Approach 2:
The monolithic optical module performs multiple functions simultaneously: it acts as a beam splitter, a reflector, and a polarization-insensitive optical element. This multi-functionality is achieved through the integrated TIR surfaces within the polymer structure, reducing the need for multiple specialized components and lowering overall manufacturing cost.
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 simplifies assembly, reduces costs, and achieves polarization-insensitive arbitrary light splitting ratios, enhancing the efficiency and flexibility of optical beam splitting in VCSEL assemblies.
Implementation Method 1
a first portion of the one or more first input optical beams may be reflected by the first TIR surface to travel in a first direction as one or more first optical beams
Data Source
AI summary
A low-cost monolithic optical module for splitting one or more input optical beams to two or more output optical beams is provided. The one or more input optical beams are reflected by two or more total internal reflection (TIR) surfaces of the monolithic optical module. A light splitting ratio between the two or more output optical beams is predetermined by one or more physical features of the two or more TIR surfaces.