Semiconductor Laser Protection Electrode Oxidation
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Solution Overview
Problem
The semiconductor laser element with a double-ridge structure often experiences low-quality insulating film formation in the shoulder area, leading to potential oxidation and disconnection of the compound semiconductor, which prevents voltage application to the saturable absorption region and hinders mode-locking operation due to electro-static discharge and anode oxidation reactions.
Innovation Solution
A protection electrode is formed adjacent to the second portion of the second electrode to divert voltage and accumulated holes, preventing oxygen ions from reacting with the compound semiconductor and thus avoiding oxidation and disconnection, ensuring reliable voltage application to the saturable absorption region.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a double-ridge structure is used in the semiconductor laser element, then the saturable absorption effect is enhanced and narrower pulse width is achieved, but the insulating film quality deteriorates in the shoulder area leading to oxidation and disconnection
Solution Approach 1:
A protection electrode is introduced as an intermediary element between the second electrode and the compound semiconductor layer. This protection electrode serves as a mediator that captures holes and prevents them from reaching the insulating film interface, thereby preventing oxidation and disconnection while allowing the double-ridge structure to maintain its superior pulse width characteristics
Solution Approach 2:
The protection electrode is positioned in advance before the harmful oxidation reaction can occur. By placing the protection electrode adjacent to the second electrode in the shoulder area, the structure proactively prevents the accumulation of holes that would otherwise cause insulating film degradation, oxidation, and disconnection
2Ease of operation
If voltage is applied to the second electrode for mode-locking operation, then self-pulsation is achieved, but accumulated holes cause oxidation of the compound semiconductor preventing reliable operation
Solution Approach 1:
The protection electrode acts as an intermediary that intercepts holes generated during voltage application for mode-locking operation. By capturing these holes before they can oxidize the compound semiconductor, the protection electrode enables stable and reliable voltage application, ensuring consistent mode-locking performance
Solution Approach 2:
The protection electrode converts the potentially harmful accumulation of holes into a beneficial effect. By intentionally providing a dedicated electrode that attracts and accumulates holes in the protection region, the design prevents hole accumulation at the insulating film interface, thereby preventing oxidation and ensuring reliable operation
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 configuration enhances the reliability and longevity of the semiconductor laser element by preventing oxidation and maintaining mode-locking operation, with no significant impact on noise characteristics or pulse width.
Implementation Method 1
which prevents voltage application to the saturable absorption region and hinders mode-locking operation due to electro-static discharge and anode oxidation reactions
Implementation Method 2
which prevents voltage application to the saturable absorption region and hinders mode-locking operation due to electro-static discharge and anode oxidation reactions
Data Source
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AI summary
A semiconductor laser element includes a stacked structure body, a second electrode 62, and a first electrode 61; a ridge stripe structure 71 formed of at least part of the stacked structure body is formed; a side structure body 72 formed of the stacked structure body is formed on both sides of the ridge stripe structure 71; the second electrode 62 is separated into a first portion for sending a direct current to the first electrode via a light emitting region and a second portion 62B for applying an electric field to a saturable absorption region; a protection electrode 81 is formed on a portion adjacent to the second portion 62B of the second electrode of at least one side structure body 72; and an insulating layer 56 made of an oxide insulating material is formed to extend from on a portion of the ridge stripe structure 71 to on a portion of the side structure body 72, on which portions neither the second electrode nor the protection electrode 81 is formed.