Apr 09: The first successful domestic development of three types of testbeds capable of real time monitoring of the performance of high power laser sources and optical modules, as well as evaluating the laser induced damage threshold(LIDT) of optical coatings, has been achieved. Using these testbeds, a 7 day continuous performance evaluation of domestic laser sources and optical lenses was successfully conducted. This development establishes a foundation for verifying the performance of Korean laser sources and optical components under criteria comparable to global standards.
Dr. Jiyeon Choi, Principal Researcher at the Department of Laser & Electron Beam Technologies of the Research Institute of Autonomous Manufacturing at the Korea Institute of Machinery and Materials, under the National Research Council of Science and Technology, has developed three types of testbeds, including two for real time monitoring of the performance of high power laser sources and optical lenses and one for evaluating the of optical coatings.
The developed evaluation system consists of a testbed that records fluctuation of in laser output under the variations of temperature and humidity conditions, a testbed that measures focal position errors caused by thermal lensing effects in optical lenses, and a testbed that evaluates the laser induced damage threshold of optical coatings. The system is equipped with an automatic shutdown function in case of abnormal laser operation, enabling safe operation even during long term monitoring. It was applied to a 1 kW domestic fiber laser and an F-theta lens, where stable performance characteristics were confirmed through a 7 day continuous evaluation.
Defects in laser-processed products are often caused by changes in the operating characteristics of laser sources and optical lenses or by performance degradation over time. However, factory-provided performance data for optical components are typically obtained under controlled laboratory conditions over short durations, making it difficult to reflect actual industrial environments. To address this limitation, the testbeds were designed to enable long term performance evaluation under harsher than real operating conditions.
The research team applied a water cooled structure and temperature sensors to key optical mounts to maintain stable performance without temperature rise during prolonged high power laser irradiation. In addition, displacement sensors were incorporated to detect distortion of the laser focal beam position caused by external vibrations, thereby improving measurement accuracy. The LIDT system supports both nanosecond pulsed lasers and continuous wave lasers, enabling evaluation of optical components for high power laser applications.
The developed testbeds have also been utilized to improve domestic products. A Korean optical component company used the testbeds to enhance lens materials and manufacturing processes and developed an F-theta lens that exhibits smaller focal position errors than imported products even under continuous exposure to a 1 kW laser for 7 days The system maintains consistent focal stability throughout extended high-power laser welding process.
Dr. Jiyeon Choi emphasized,
“Laser processing systems are essential equipment for key industries such as semiconductors, automotive, and secondary batteries, but domestic manufacturers struggle to secure objective performance data due to a prevailing market preference for foreign equipment among major end-users.” She added, “The newly developed testbeds enable not only ISO standard based validation but also customized long term evaluations beyond 7 day continuous evaluation,, allowing reliable performance data to be obtained under real operating conditions and contributing to strengthening the competitiveness of domestic equipment.”
This research was conducted by the Department of Laser & Electron Beam Technologies at KIMM under the project titled “Development of the reliability improvement techniques for laser processing system and core optical components” supported by the Ministry of Trade, Industry and Resources.
