Semiconductor Laser Device Tapered Optical Guide Layer
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Solution Overview
Problem
Semiconductor laser devices used as pump lasers in optical amplifiers face challenges in achieving high output and low power consumption due to issues like gain saturation and varying electric field confinement factors, which are difficult to manage with existing tapered waveguide configurations.
Innovation Solution
A semiconductor laser device design incorporating an electric field control layer with a shorter composition wavelength and an optical guide layer extending in the optical waveguide direction, where the width of the optical guide layer is changed to reduce light density and prevent gain saturation, while maintaining a constant active layer width to stabilize electric field confinement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If a tapered waveguide is adopted to reduce light density and prevent gain saturation, then optical power is improved, but the electric field confinement factor in the active layer largely varies depending on the width of the active layer, making it difficult to achieve desired high output characteristics
Solution Approach 1:
The patent divides the waveguide structure into functionally distinct segments: the active layer maintains a constant width to ensure stable electric field confinement, while the optical guide layer separately handles the tapered width variation to control light density. This segmentation allows independent optimization of each function without mutual interference.
Solution Approach 2:
The patent applies different geometric properties to different parts of the waveguide structure. The active layer maintains uniform width (constant cross-section) to provide consistent electric field confinement, while the optical guide layer features variable width (tapered cross-section) to locally adjust light density along the propagation direction.
2Use of energy by moving object
If the cavity length is increased to reduce electrical resistance and achieve low power consumption, then electrical resistance is improved, but a light distribution occurs in the resonator causing gain saturation and reduced optical power
Solution Approach 1:
The patent changes the geometric parameters of the optical guide layer, specifically implementing a tapered width profile along the propagation direction. This parameter change modifies the light distribution pattern in the resonator, preventing the formation of high-density regions that cause gain saturation, thereby maintaining high optical power even with increased cavity length.
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 design achieves high output characteristics by stabilizing the electric field confinement factor and reducing light density at the front facet, thereby enhancing the semiconductor laser device's performance.
Implementation Method 1
buried layers made of a material having a lower refractive index than the optical guide layer are arranged at both sides of the optical guide layer in the width direction
Implementation Method 2
a technology for providing a layer with a high refractive index (also referred to as an electric field control layer) in an n-type cladding layer, and skewing a distribution of an electric field of laser light that propagates through an active layer to the n-type cladding layer side
Data Source
AI summary
A semiconductor laser device includes: a main body including a first layer having n-type conductivity, a second layer having p-type conductivity, and an active layer interposed between the first layer and the second layer, the first layer, the second layer, and the active layer being laminated in a lamination direction; a front-side mirror formed on a front facet of the main body, the front facet being parallel to the lamination direction; and a rear-side mirror formed on a rear facet of the main body, the rear facet facing the front facet in an optical waveguide direction that crosses the lamination direction and the front facet. The first layer includes an electric field control layer having a shorter composition wavelength than an emission wavelength of the active layer. The second layer includes an optical guide layer having a shorter composition wavelength than the emission wavelength of the active layer.