VCSEL Surface-Emitting Laser With Slow Light Amplification
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Solution Overview
Problem
Conventional surface-emitting lasers face limitations in achieving high-power output beyond the mW level, with array structures providing high output but suffering from non-uniform phase and wavelength, leading to wide oscillation spectrum width and large beam divergence, while photonic crystal structures are challenging to manufacture reliably.
Innovation Solution
A surface-emitting laser design incorporating a VCSEL and slow light SOA arranged laterally, with a seed light source and output unit sharing a VCSEL structure, featuring a relation between seed light and oscillation wavelengths to suppress return light and improve beam quality, and incorporating an air gap layer, low-refractive-index layers, and a zig-zag output unit configuration to enhance power output.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If array structure is employed to provide high output, then power output is improved to 10 W or more, but beam quality deteriorates with wide oscillation spectrum width and large beam divergence angle
Solution Approach 1:
The laser system is segmented into multiple individual laser elements arranged in an array, where each element maintains uniform phase and wavelength characteristics independently. This segmentation allows high total power output while preserving beam quality through coherent combination of individual elements.
Solution Approach 2:
Multiple laser elements are merged into a unified array structure with shared optical components and control systems. The individual elements are coherently combined to achieve high power output while maintaining uniform phase and wavelength, resolving the contradiction between power and beam quality.
2Stability of the object's composition
If surface-machined structure is used to suppress high-order mode oscillation, then beam quality is improved, but power output is limited to 10 mW or less
Solution Approach 1:
The invention transitions from two-dimensional surface-machined structures to three-dimensional volume-based distributed feedback structures. This dimensional change enables suppression of high-order modes through volumetric optical feedback rather than surface relief, allowing higher power output while maintaining beam quality.
3Power
If photonic crystal structure is employed to support watt-class high-power output, then power output is improved, but manufacturing complexity increases with fine cyclic structure requirements
Solution Approach 1:
The invention employs dynamically adjustable optical feedback mechanisms rather than static fine cyclic photonic crystal structures. This allows watt-class power output through controllable distributed feedback, reducing manufacturing complexity while maintaining high power capability.
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 design achieves high-power output with improved beam quality, narrow spectrum width, and reduced size and cost, supporting watt-class high-power operation.
Implementation Method 1
the seed light propagates as a slow light through the VCSEL structure in a longitudinal direction while being reflected multiple times in the VCSEL structure in a vertical direction
Implementation Method 2
an output light is extracted from an upper surface of the VCSEL structure
Data Source
Figure 1
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AI summary
A surface-emitting laser 1 includes an output unit 4. The output unit 4 has an oblong-shaped VCSEL (vertical-cavity surface-emitting laser) structure. The output unit 4 operates in an oscillation state in which a current that is larger than the oscillation threshold value is injected. The output unit 4 receives a coherent seed light via a coupling surface 3 at one end of the VCSEL structure in the longitudinal direction thereof. The seed light thus received propagates as a slow light through the VCSEL structure in the longitudinal direction thereof while being reflected multiple times in the vertical direction within the VCSEL structure. An output light L2 is extracted from the upper surface of the VCSEL structure.