1.3 μm Tunable DBR Laser Barrier Layers for Wider Wavelength Tuning
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Solution Overview
Problem
1.3 μm-band wavelength-tunable DBR lasers face limitations in refractive index change and wavelength-tunable amount due to increased effective mass of InGaAsP materials, resulting in insufficient wavelength tuning capabilities compared to 1.55 μm-band lasers.
Innovation Solution
Incorporating p-type and n-type doped carrier barrier layers with larger bandgaps than the clad layers at the boundaries between the clad and core layers in the DBR region, enhancing carrier confinement and density, thereby increasing the wavelength-tunable range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If InGaAsP materials are used in 1.3 μm-band DBR lasers, then the laser can operate at the desired wavelength, but the effective mass increase reduces the refractive index change and wavelength-tunable amount
Solution Approach 1:
The patent applies local quality by introducing carrier barrier layers with specific doping types (p-type and n-type) and larger bandgaps at specific locations (boundaries between clad and core layers in the DBR region). These localized structures create strong carrier confinement exactly where needed in the DBR region, enhancing the refractive index change and wavelength-tunable amount without requiring changes to the entire laser structure.
Solution Approach 2:
The patent uses composite material structures by combining different semiconductor materials with varying bandgaps (InGaAsP core layer with InP or InAlAs barrier layers). This composite approach allows the system to leverage the beneficial properties of each material: the InGaAsP provides the desired 1.3 μm wavelength operation, while the InP or InAlAs barrier layers provide stronger carrier confinement and larger refractive index changes.
2Measurement precision
If carrier barrier layers with larger bandgaps are introduced at the boundaries between clad and core layers, then carrier confinement and density are enhanced, but the device structure becomes more complex
Solution Approach 1:
The patent applies segmentation by dividing the DBR region into distinct functional layers: core layers for optical confinement, clad layers for structural support, and intermediate carrier barrier layers for carrier management. This segmentation allows each layer to be optimized for its specific function while maintaining overall system performance. The barrier layers are strategically positioned at the boundaries to create localized carrier confinement without requiring complete restructuring of the entire DBR region.
3Measurement precision
If p-type and n-type doped carrier barrier layers are added to enhance carrier confinement, then manufacturing processes become more difficult
Solution Approach 1:
The patent merges multiple functions into the carrier barrier layers: they serve as both structural boundaries between core and clad regions and as doping regions for carrier confinement. By combining the boundary function and carrier management function into a single integrated layer structure, the patent reduces the need for separate manufacturing steps while achieving enhanced carrier density and 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
The introduction of doped carrier barrier layers significantly enhances the wavelength-tunable amount of 1.3 μm-band DBR lasers, achieving a wavelength-tunable range comparable to 1.55 μm-band lasers, with improved carrier confinement and density, and maintaining single-mode operation.
Implementation Method 1
a p-type-doped electron barrier layer with a larger bandgap than a p-side clad layer at the boundary between the p-side clad layer and a core layer in the DBR region. The wavelength-tunable DBR laser further includes a n-type-doped hole barrier layer with a larger bandgap than a n-side clad layer at the boundary between the n-side clad layer and a core layer in the DBR region.
Implementation Method 2
a wavelength-tunable DBR laser that uses a carrier plasma effect in which a wavelength can be varied at a high speed
Data Source
AI summary
A 1.3 μm-band wavelength-tunable DBR laser in which a wavelength-tunable amount is extended is disclosed. The wavelength-tunable DBR laser according to an embodiment of the present invention is a wavelength-tunable DBR laser in which an active region having an optical gain and a DBR region including a diffraction grating are integrated monolithically and an oscillation wavelength is changed by injecting a current into the DBR region. At a boundary between a p-side clad layer and a core layer in the DBR region, an electron barrier layer being p-type doped and having a bandgap greater than in the p-side clad layer is further included. At a boundary between an n-side clad layer and the core layer in the DBR region, a hole barrier layer being n-type doped and having a bandgap greater than in the n-side clad layer is further included.