Planar Waveguide Multilayer Cladding Low Index Core
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Solution Overview
Problem
Conventional planar waveguides face limitations in using materials with low refractive indices as cores, as finding claddings with lower refractive indices than the core is challenging, restricting the choice of core materials.
Innovation Solution
The use of multilayer films as claddings, composed of different dielectric materials, allows for the reflection of light and confinement within the core, enabling the use of materials with low refractive indices as the core by satisfying specific conditions for film thickness and refractive indices, which are not limited by the core's refractive index.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a material with low index of refraction is used as the core material, then the optical characteristics are improved, but it becomes difficult to find cladding materials with lower index of refraction
Solution Approach 1:
The cladding is segmented into multiple thin films with alternating high and low refractive indices. This segmentation allows the cladding structure to achieve effective lower refractive index behavior for light confinement while using individually available materials, thus resolving the contradiction between using low-index core materials and finding suitable cladding materials.
Solution Approach 2:
The cladding is constructed as a composite multilayer structure combining materials with different refractive indices. This composite approach creates an effective optical medium with properties different from individual layers, enabling the cladding to provide the necessary light confinement for low-index core materials while using practically available materials.
2Device complexity
If conventional single-layer cladding is used, then the structure is simple, but light cannot be effectively confined when core material has low index of refraction
Solution Approach 1:
The cladding is divided into multiple thin film layers with alternating refractive indices. This segmentation creates a photonic bandgap structure that effectively confines light within the core, providing reliable light confinement even when the core has low refractive index, thus resolving the contradiction between structural simplicity and confinement effectiveness.
Solution Approach 2:
The invention changes the optical parameters of the cladding by using multiple layers with different refractive indices and controlled thicknesses. This parameter optimization enables effective light confinement for low-index core materials, resolving the contradiction between maintaining simple structure and achieving reliable confinement.
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 configuration allows for the confinement of light within the core, reducing waveguide loss and enabling the use of low-index materials as the core, while allowing only low-order mode propagation, thus overcoming the limitations of conventional designs.
Implementation Method 1
light incident upon the core is totally reflected at the interface between each of the first and second claddings and the core
Data Source
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AI summary
Disclosed is a planar waveguide including: a core (11) which is a flat plate through which light propagates; a cladding (12) which is a flat plate for reflecting the light in a state of being joined to an upper surface of the core (11); and a cladding (13) which is a flat plate for reflecting the light in a state of being joined to a lower surface of the core (11), in which each of the claddings (12) and (13) is a multilayer film in which multiple films made from different materials are layered. As a result, a material having a low index of refraction can be used as the material of the core (11), and the limit on materials usable as the material of the core (11) is relaxed.