Semiconductor Laser Contact Layout for Facet Reliability at High Power
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Solution Overview
Problem
High-power CW semiconductor lasers experience significant failure rates due to facet-related issues, particularly at high current and power levels, such as 65 mW/320 mA at 85° C.
Innovation Solution
The semiconductor laser design includes a conductive contact with a central area less than the cavity length and/or a dielectric layer on the contact layer end portions, reducing current density at the facet edges by pulling back or covering these areas with dielectric material.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If high current and power are applied to achieve high power output, then power output is improved, but facet reliability deteriorates due to excessive current density at facet edges
Solution Approach 1:
The patent applies different properties to different regions of the contact layer. The central region maintains high conductivity for current injection, while the edge regions are covered with dielectric material to reduce current density. This local differentiation allows the device to operate at high power without excessive current concentration at the facets, thereby maintaining facet reliability while achieving high power output.
2Reliability
If current density at facet edges is reduced to improve facet reliability, then facet reliability is improved, but current distribution uniformity worsens
Solution Approach 1:
The contact layer is designed with non-uniform conductivity distribution. The central region has high conductivity for effective current injection, while the edge regions are covered with dielectric material to reduce current density. This local differentiation allows the device to operate at high power without excessive current concentration at the facets, thereby maintaining facet reliability while achieving high power output.
Data Source
AI summary
Described herein are examples of improved semiconductor lasers having improved facet reliability for operation at high power and high current without significant change in device performance. The semiconductor laser may include a first semiconductor layer, an active layer, a second semiconductor layer sequentially adjacent to each other and arranged on a substrate, and a contact layer. In one example, the improved semiconductor laser may have a conductive contact less than the length of the semiconductor laser cavity and/or a dielectric layer arranged on at least one of the end portions of the contact layer.