Study On Time Domain Modulation Characteristics Of High Power Yb - Doped Fiber

High power fiber laser with its high brightness, high power, tunable, and many other advantages, has been applied in optical communications, medical, military, laser processing, and other important areas. In order to meet the actual demand of the output optical power and the working speed of the fiber laser in metal processing and 3D printing industry, this paper studied the time domain modulation characteristics of high power ytterbium doped fiber laser system, realized stable modulated pulse laser output of 500W continuous ytterbium doped fiber laser whose largest modulation frequency is 10kHz, and the duty ratio is adjustable,First, this paper was based on the constant current theory of laser power supply, then we obtained the output current with high 0-36A and long working stability by digital switching power supply and constant current source circuit based on field effect, and we solved the current overshoot and oscillation problem in the time domain by adjusting the driving voltage of laser power supply, then we realized the stable modulation current output with adjustable frequency and duty cycle. Secondly, according to the requirement of the high power fiber laser for the pumping light source, we studied the time domain modulation characteristics of semiconductor lasers by direct current modulation, and obtained the modulated laser output with short optical delay and high signal response. In the end, we studied the modulation characteristics of 500W continuous ytterbium doped fiber laser, who was directly pumped by modulated pumped light, then we obtained the relationship between the output optical power, the photoelectric delay time and the modulation frequency and the pulse width. In addition, we studied the Q phenomenon of the laser in the modulation process, obtained the relationship between the pulse width of the giant pulse generated by laser modulated Q and the driving current. Aiming at the problem of giant pulse output generated by laser modulated Q, We suppressed the output pulse effectively by increasing the bias current, finally, we realized the stable modulated pulse laser output of 500W continuous fiber laser whose modulation frequency is less than 10kHz, and the duty ratio is adjustable.