Method and apparatus for driving diode pumped solid-state lasers

A method for driving a diode-pumped solid-state laser, comprising the steps of:

• determining a measurement signal as an actual value of light power emitted by the solid-state laser;
• in a first feedback path, determining a control deviation by comparing the measurement signal with a predetermined light power target value;
• converting the determined control deviation into a driver current for a laser diode used as a pump diode for a resonator of the solid-state laser;
• in a separate second feedback path parallel to the first feedback path, filtering out higher-frequency components of the measurement signal for damping of corresponding higher-frequency disturbances of the light power;
• and
• controlling a portion of the driver current supplied to the laser diode dependent on the filtered-out higher-frequency components of the measurement signal, said portion being 0.5 to 50% of the driver current.

An apparatus for driving a diode-pumped solid-state laser, comprising:

• a solid-state laser with a resonator;
• a laser diode used as a pump diode for the resonator;
• a measurement unit for determining a measurement signal as an actual value of light power emitted by the solid-state laser;
• a first control circuit receiving said measurement signal and having a control amplifier for determining a control deviation by comparison of the measurement signal with a predetermined light power target value;
• a converter connected downstream from the control amplifier for producing a driver current for the laser diode, said current corresponding to said determined control deviation;
• a second control circuit having a high-pass filter connected to receive said measurement signal for filtering out higher-frequency components from the measurement signal corresponding to higher-frequency disturbances of the light power;
• a fast control amplifier connected downstream from the high-pass filter;
• and
• a control element connected to the fast control amplifier for controlling a portion of the driver current supplied to the laser diode dependent on the filtered-out, higher-frequency components of the measurement signal, said portion being 0.5 to 50% of the driver current.

An apparatus for driving a diode-pumped solid-state laser, comprising:

• a solid-state laser with a resonator;
• a laser diode used as a pump diode for the resonator;
• a measurement unit for determining a measurement signal as an actual value of light power emitted by the solid-state laser;
• a first feedback path having a first control circuit receiving said measurement signal for determining a control deviation by comparison of the measurement signal with a predetermined light power target value, and for producing a driver current for the laser diode, said current corresponding to said determined control deviation;
• and
• a second feedback path parallel to the first feedback path and having a second control circuit connected to receive said measurement signal for filtering out higher-frequency components from the measurement signal corresponding to higher-frequency disturbances of the light power, for controlling a portion of the driver current supplied to the laser diode dependent on the filtered-out, higher-frequency components of the measurement signal, said portion being 0.5 to 50% of the driver current.