Optical Waveguide Cladding Segmentation for Accurate Coupling Measurement
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Solution Overview
Problem
Existing optical axis adjustment methods for optical waveguides face challenges in achieving high-efficiency optical coupling of incident light due to issues such as reflective light disappearance, light loss through high-refractive-index layers, and difficulty in separating light incident on the waveguide from the clad, leading to inefficient propagation and coupling.
Innovation Solution
The optical waveguide element features a structure with inclined cladding surfaces and a rough surface on one clad, combined with an optical axis adjustment method using a power meter and imaging device to adjust the position and angle of the light source and lens, ensuring efficient optical coupling by minimizing scattered light and maximizing emission light output.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the optical axis adjustment is performed by maximizing the output light from the emission end surface, then the alignment of lens and light source can be optimized, but it cannot distinguish whether the light is coupled to the waveguide or merely propagating through the clad
Solution Approach 1:
The patent divides the emission end surface into two distinct regions: a waveguide emission region and a clad emission region. By spatially separating these regions, the system can independently measure light from each region. The waveguide emission region provides accurate optical coupling measurement, while the clad emission region serves as a reference for unwanted light, thereby resolving the contradiction between measurement accuracy and coupling efficiency.
Solution Approach 2:
The patent introduces an inclined surface as an intermediary structure between the clad and the external environment. This inclined surface redirects light propagating through the clad away from the emission end surface, preventing it from contaminating the measurement. This intermediary structure enables accurate distinction between waveguide-coupled light and clad-propagating light.
2Device complexity
If a conventional flat-clad structure is used, then the device structure is simple, but light propagating through the clad is totally reflected and exits from the emission end surface, contaminating the measurement
Solution Approach 1:
The patent applies asymmetry by introducing an inclined surface on one side of the clad while maintaining a flat surface on the other side. This asymmetric structure selectively redirects light propagating through the clad away from the emission end surface, while preserving the simple flat structure where needed. This resolves the contradiction by adding minimal structural complexity only where necessary to improve measurement accuracy.
Solution Approach 2:
The inclined surface serves multiple functions: it redirects unwanted clad light, defines the boundary between waveguide and clad emission regions, and maintains structural simplicity. This multi-functional design achieves high measurement precision without proportionally increasing device complexity.
3Quantity of substance
If the emission end surface area is increased to improve light collection, then more light can be detected, but light from both waveguide and clad mixes together making separation difficult
Solution Approach 1:
The emission end surface is segmented into distinct waveguide emission and clad emission regions by the inclined surface. This segmentation allows the system to collect light from both regions while maintaining clear spatial separation, enabling independent measurement of each light source without mixing.
Solution Approach 2:
The inclined surface acts as an intermediary that spatially separates the emission paths of waveguide and clad light. By redirecting clad light at a specific angle, it creates distinct emission zones that can be independently detected, allowing the system to maximize light collection while maintaining measurement precision.
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
This approach allows for easy and efficient optical coupling of incident light to the waveguide, enhancing propagation efficiency by optimizing the alignment of the focal point and beam angle, thereby maximizing the output of emission light.
Implementation Method 1
a rough surface formed on an upper surface of the upper clad... the components of the incident light 10 which are not optically coupled to the waveguide 2 are scattered from the rough surface 5 of the upper clad 3b to the outside of the optical waveguide element 100
Implementation Method 2
a reflective surface formed on a lower surface of the lower clad 3a... the components of the incident light 10 which are not optically coupled to the waveguide 2 are scattered from the rough surface 5 of the upper clad 3b to the outside of the optical waveguide element 100
Implementation Method 3
a step of condensing light from a light source by a lens on the incident end surface of the optical waveguide element
Data Source
AI summary
An optical waveguide element of the present disclosure includes: a waveguide for propagating light; a clad including an upper clad whose lower surface is in contact with one surface of the waveguide and whose upper surface exposed to the outside is formed with a rough surface, and a lower clad whose upper surface is in contact with the other surface of the waveguide and whose lower surface is formed with a reflective surface; an incident end surface provided at one end of the waveguide and the clad; and an emission end surface provided at the other end of the waveguide and the clad, whereby incident light is optically coupled to the waveguide with high efficiency.