VCSEL Circular Metal Electrode Single-Mode Operation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing vertical-cavity surface emitting lasers (VCSELs) with small oxide apertures suffer from increased device resistance and thermal effects, leading to early damping and reduced efficiency, limiting the oxide aperture size to below 3 μm.
Innovation Solution
A VCSEL design incorporating a circular metal electrode and an oxide aperture between 5 μm and 10 μm, where the electrode reflects non-fundamental modes of the laser beam, allowing only the fundamental mode to pass through, thereby increasing the aperture size and reducing damping.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the oxide aperture is increased to reduce device resistance and thermal effects, then the efficiency and transmission distance are improved, but the single-mode operation becomes difficult to maintain due to increased damping
Solution Approach 1:
The invention divides the aperture control function into two separate components: the oxide aperture for electrical confinement and the circular concave for optical mode selection. This segmentation allows the oxide aperture to be enlarged for reduced resistance without compromising single-mode operation, as the circular concave independently controls the optical mode through its geometric design.
Solution Approach 2:
The circular concave acts as an intermediary structure between the enlarged oxide aperture and the output beam. It mediates the optical field distribution by providing a geometric constraint that selects the fundamental mode, thereby enabling the oxide aperture to be larger without directly causing mode instability or increased damping.
2Stability of the object's composition
If a high aluminum-containing layer is used to limit the laser beam for single-mode operation, then the oxide aperture is reduced below 3 μm, but the device resistance increases and thermal effects become more obvious
Solution Approach 1:
The invention separates the beam limitation function from the electrical confinement function. The circular concave structure assumes the beam limitation role for single-mode operation, while the oxide aperture focuses on electrical confinement with a larger size, thereby reducing device resistance and thermal effects without compromising single-mode stability.
Solution Approach 2:
The invention changes the geometric parameters of the circular concave (depth, diameter, curvature) to optimize optical mode selection. By adjusting these parameters, the circular concave can effectively limit the laser beam to fundamental mode while allowing the oxide aperture to maintain a larger size for reduced electrical resistance.
3Stability of the object's composition
If the oxide aperture is made smaller to maintain single-mode operation, then the device resistance increases, but the thermal effects become more obvious resulting in earlier damping
Solution Approach 1:
The invention divides the aperture control function into two separate components: the oxide aperture of larger size for electrical confinement with reduced resistance, and the circular concave for optical mode selection. This segmentation allows thermal management to be improved through the larger oxide aperture without compromising single-mode operation, as the circular concave independently maintains mode stability.
Solution Approach 2:
The circular concave serves as an intermediary that decouples the relationship between aperture size and mode stability. It mediates the optical field to ensure fundamental mode operation while allowing the oxide aperture to be enlarged for reduced thermal effects and resistance.
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 effectively addresses the early damping issue and enhances the efficiency of the VCSEL by allowing a larger oxide aperture while maintaining single-mode operation, increasing the transmission distance in optical fibers.
Implementation Method 1
the circular metal electrode is used for reflecting other modes of the plurality of modes of the laser beam except for a fundamental mode of the plurality of modes of the laser beam
Implementation Method 2
the at least one quantum well generates a laser beam with a plurality of modes
Implementation Method 3
the first reflector is an N-type distributed Bragg reflector, and the first reflector is formed by stacking a plurality of N-type low-refractive-index semiconductor materials and a plurality of N-type high-refractive-index semiconductor materials alternately
Data Source
AI summary
A vertical-cavity surface emitting laser includes a substrate, a first reflector, an active region, an oxide layer, a second reflector, and a circular metal electrode. The first reflector is formed above the substrate. The active region is formed above the first reflector, and includes at least one quantum well. The at least one quantum well generates a laser beam with a plurality of modes. The oxide layer is formed above the active region and includes an oxide aperture. The second reflector is formed above the oxide layer. The circular metal electrode is formed in a circular concave in the second reflector. The circular metal electrode reflects other modes of the laser beam with the plurality of modes except for a fundamental mode and receive an operational voltage. A window exists between the circular concave and lets the laser beam with the fundamental mode pass.