Fiber feedback controlled, power and spectral regulated high power laser module for laser welding

In the context of welding plastics in the automotive, food, and furniture industries, there is an increasing demand for laser sources that exhibit higher processing speeds and precision. The methodologies developed in this study are characterised by their narrow process windows, and fluctuations in laser power can result in the formation of faulty weld seams and compromised functionality. In the food industry, the welding of packaging can present a potential hazard to consumers. To address this challenge, a precise power and spectral stabilisation technique has been employed for high-power diode lasers, utilising a fibre connector-based feedback control mechanism. A special fibre preparation is utilised to detect the scattered radiation, with the fluctuations being measured using the optical signal. This signal is recorded by a detector, with amplitude adjustment being performed if necessary using specially developed electronics. The signal is then sent to the FPGA unit as feedback. The FPGA unit supplies the calculated PID controller values for the entire amplitude range with millisecond latency. The output signal of the FPGA unit is fed into the electronic circuit for signal adjustment and forwarded to the laser. The laser module is characterised by an optical power output of up to 100 W, a power regulation accuracy of milliseconds, and a power stability of ± 0.1%. It is a fibre-feedback controlled, power-and spectral-regulated high-power laser module designed specifically for laser welding applications.