Semiconductor Laser Element With Reduced Optical Confinement
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Solution Overview
Problem
Semiconductor laser devices face challenges in achieving high wall plug efficiency (WPE) and efficient coupling of laser light to optical fibers, particularly in high-power applications where multi-mode operation is required, leading to issues with power distribution and reliability.
Innovation Solution
A semiconductor laser device with a multi-mode oscillation capability, featuring a semiconductor layer portion with first and second regions, where the second region has reduced optical confinement and no current injection, allowing for improved coupling efficiency by optimizing the length and structure of these regions to minimize high-order horizontal lateral mode confinement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the waveguide width is increased to accept multiple modes for high power output, then the power output capability is improved, but the coupling efficiency to optical fiber deteriorates due to increased divergence angle
Solution Approach 1:
The semiconductor layer is divided into multiple regions along the light propagation direction: a first region with strong optical confinement (ridge structure) for mode control, and a second region with reduced optical confinement for divergence reduction. This segmentation allows different functional zones to address different requirements simultaneously.
Solution Approach 2:
The invention transitions from controlling only the horizontal waveguide width to also controlling the vertical optical confinement. By adjusting the ridge height and introducing a second region with reduced confinement, the patent adds a vertical dimension to mode control, enabling independent optimization of power output and beam divergence.
2Stability of the object's composition
If strong optical confinement is maintained throughout the entire semiconductor layer to control laser modes, then the mode control is improved, but the coupling efficiency to optical fiber deteriorates due to increased far-field divergence angle
Solution Approach 1:
The semiconductor layer is segmented into a first region with strong optical confinement for mode control and a second region with reduced optical confinement for divergence reduction. This allows the laser to maintain stable modes in the first region while achieving better coupling in the second region.
Solution Approach 2:
The optical confinement strength is dynamically adjusted along the light propagation direction. The first region provides strong confinement for mode stabilization, while the second region reduces confinement to decrease the far-field divergence angle, creating a dynamic transition in confinement characteristics.
3Stability of the object's composition
If the ridge structure is extended throughout the entire semiconductor layer for optical confinement, then the mode control is improved, but the device complexity and manufacturing difficulty increase
Solution Approach 1:
Instead of extending the ridge structure throughout the entire layer, the patent segments it into a first region with full ridge structure for mode control and a second region with reduced or eliminated ridge structure for divergence control. This segmentation simplifies manufacturing while maintaining optical performance.
Solution Approach 2:
The ridge structure is extracted or removed from the second region while being maintained in the first region. This selective removal reduces structural complexity and manufacturing difficulty in the output region where optical confinement is less critical.
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 enhances coupling efficiency to optical fibers, reduces the angle of the far-field pattern, and maintains appropriate optical power distribution, thereby improving the overall performance and reliability of the semiconductor laser device.
Implementation Method 1
an optical confinement effect of the laser light to the stripe region in a horizontal direction
Implementation Method 2
a semiconductor layer portion having an active layer and performs multi-mode oscillation of laser light
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
A semiconductor laser device includes a semiconductor layer portion having an active layer and performs multi-mode emission of laser light. The semiconductor layer portion includes a first region, and a second region located closer to a facet on a laser light radiation side than the first region. The first region and the second region include a stripe region in which the laser light is guided, and an optical confinement effect of the laser light to the stripe region in a horizontal direction of the second region is less than that of the stripe region. Accordingly, a semiconductor laser device having a favorable coupling efficiency to an optical fiber is provided.