LASER MARKING SYSTEM AND METHOD OF ENERGY CONTROL

摘要

A laser marking system comprises a high power fiber laser consisting of a double clad fiber having a doped core surrounded by an inner pump cladding and providing an optical output for marking; a high power laser diode source for pumping the double clad fiber laser via an input into the inner pump cladding; an optical scanner coupled to receive the marking output from the double clad fiber laser to scan the output over a surface of an article to be marked by sweeping the marking output in one, two or three dimensions to form strokes, the completion of which comprises indicia to be marked the article surface; and a controller to control the operation of the scanner in synchronism with the modulation of the laser diode pump source to initiate the marking output and sweep and modulate the marking optical output in one, two or three dimensions to form strokes comprising the indicia. A main advantage of the fiber laser marking system over CO2 and YAG laser marking systems is the ability to provide modulation via the semiconductor laser diode at the input to the marking laser rather than having to modulate the optical power beam at the output of the marking laser, such as through an acusto-optic modulator, which provides for a pulse of non-uniform stability across the pulse width with a substantially decrease in the amount of power in the modulated beam output. Also disclosed is circuitry to dampen the ON-time rise of a current signal input for operation of the laser diode pump source to improve the ON-time quality of the marking optical output created by the double clad fiber marking laser.