Distributed Feedback Light Source With Metal Layer Mode Confinement
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Solution Overview
Problem
Integration of III-V light sources with distributed feedback resonant cavities onto silicon substrates faces challenges due to high optical losses, as silicon has a higher optical index than III-V materials, leading to coupling of guided modes with the substrate and reduced confinement efficiency.
Innovation Solution
Incorporating a relatively thick lower cladding layer or using a low optical index layer between the lower cladding layer and the silicon substrate to reduce coupling, and replacing the oxide or nitride layer with a metal layer, such as gold, silver, or titanium, to improve confinement and reduce optical losses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a thick lower cladding layer is used to reduce coupling with the silicon substrate, then optical losses are reduced, but the device complexity and manufacturing difficulty increase
Solution Approach 1:
The patent introduces an intermediate layer with intermediate optical index positioned between the low-index lower cladding layer and the high-index silicon substrate. This intermediary layer acts as a gradient index transition that reduces the abrupt index mismatch, thereby minimizing optical coupling losses between the guided mode and the silicon substrate while maintaining manageable layer thicknesses and device complexity.
2Reliability
If the lower cladding layer is made thick to compensate for penetration depth, then confinement effectiveness is improved, but the manufacturing cost and integration difficulty increase
Solution Approach 1:
The patent modifies the optical index parameter by introducing an intermediate layer with optical index positioned between that of the lower cladding layer and the silicon substrate. This parameter change creates a gradual index transition that improves confinement effectiveness without requiring excessive thickness of the lower cladding layer, thereby simplifying manufacturing and integration processes.
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 effectively reduces optical losses and improves the confinement of resonant guided modes, allowing for the integration of III-V light sources on high-index substrates with a reduced footprint and a wide spectral range.
Implementation Method 1
The lower confinement layer is in direct contact with the lower metal layer... configured so that at least one stationary mode of an electromagnetic field, called a 'resonant guided mode'.is established parallel to the substrate
Implementation Method 2
The active region is configured to emit an electromagnetic field, by spontaneous and/or stimulated emission
Implementation Method 3
The active region is configured to emit an electromagnetic field, by spontaneous and/or stimulated emission
Implementation Method 4
A diffraction grating makes it possible to apply a feedback to the magnetic field to establish the guided modes
Data Source
Figure 1
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Figure 3~4
AI summary
One aspect of the invention relates to a distributed feedback light source (101) comprising a stack of layers (103) extending parallel to a substrate (102), the source (101) also comprising a first metal layer (111) extending between the substrate (102) and the stack (103).