Laser Diode Cleavage Structure for Uniform Waveguide End Faces
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Solution Overview
Problem
The variation in the shape of the end face of a laser diode element's optical waveguide due to cleavage can lead to inconsistent characteristics among the laser beams emitted, affecting the performance and consistency of the laser diode element.
Innovation Solution
A method involving the preparation of a stacked body with defined cleavage and division lines, where protrusions with specific side surfaces and ridges are formed to ensure uniform distances between these features, allowing precise cleavage and reducing variations in the end face shape, thereby stabilizing the laser beam characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the stacked body is cleaved along planned cleavage lines to form laser diode elements, then the laser diode elements can be manufactured efficiently, but the shape of the end face varies due to the shape of the stacked body, causing variation in laser beam characteristics
Solution Approach 1:
The patent applies preliminary action by forming protrusions with specific side surfaces and ridges on the stacked body before the cleavage process. These pre-formed structural features guide the cleavage to produce uniform end faces across multiple laser diode elements. The protrusions are positioned and shaped in advance so that when cleavage occurs along planned cleavage lines, the end faces of all elements have consistent shapes, thereby reducing variation in laser beam characteristics while maintaining efficient manufacturing
Solution Approach 2:
The patent applies local quality by creating non-uniform protrusions with asymmetric side surfaces at specific locations on the stacked body. Each protrusion has a first side surface and a second side surface with different distances to the ridge, and different inclination angles. This local structural variation is deliberately designed to compensate for variations in the stacked body shape, ensuring that after cleavage, all laser diode elements obtain end faces with uniform shapes and consistent optical waveguide characteristics
2Ease of manufacture
If the end face shape varies due to stacked body shape, then manufacturing is simpler, but the characteristics of the plurality of laser beams become inconsistent
Solution Approach 1:
The patent forms protrusions with specific side surfaces and ridges on the stacked body before cleavage. These pre-formed features ensure that when the stacked body is cleaved along planned cleavage lines, each laser diode element obtains an end face with a uniform shape. This preliminary structuring maintains manufacturing simplicity while ensuring consistent laser beam characteristics across all elements
Solution Approach 2:
The patent changes the geometric parameters of the protrusions, specifically setting the first distance from the first side surface to the ridge as equal across all protrusions, while the second distance from the second side surface to the ridge varies. This parameter control ensures uniform end face shapes after cleavage, improving laser beam consistency without significantly complicating the manufacturing process
Data Source
AI summary
A method for manufacturing a laser diode element includes preparing a stacked body including a nitride semiconductor substrate, a first conductivity type semiconductor layer, an active layer, and a second conductivity type semiconductor layer. Element regions are defined by planned cleavage lines and planned division lines. The stacked body defines protrusions each including first and second side surfaces, and a ridge. Lower ends of the first and second side surfaces are located below a lower surface of the active layer. A first distance from the first side surface to the ridge is different from a second distance from the second side surface to the ridge. The first distance is the same for all of the protrusions in the at least one of the element regions. The stack body is cleaved from the first side surface to the second side surface.