High power pulsed light generation device
A high power pulsed light generation device includes: a master clock generator that generates a master signal; an optical oscillator that generates a pulsed light synchronized with the master clock signal; an optical amplifier that amplifies the pulsed light emitted from the optical oscillator to output a high power pulsed light; a pump semiconductor laser that generates a pulsed light for pumping the optical amplifier; a driving unit that drives the pump semiconductor laser by a pulsed driving current synchronized with the master clock signal; and a control unit which controls the driving unit and controls a gain of the optical amplifier for each pulse by changing a pulse width of the pulsed drive current from driving unit so as to change the pulse width of the pumping pulsed light.
1. A high power pulsed light generation device comprising:
a master clock generator that generates a master clock signal;
an optical oscillator that generates a pulsed light synchronized with the master clock signal;
an optical amplifier that amplifies the pulsed light emitted from the optical oscillator to output a high power pulsed light;
a pump semiconductor laser that generates a pulsed light for pumping the optical amplifier;
a driving unit that drives the pump semiconductor laser by a pulsed driving current synchronized with the master clock signal; and
a control unit which controls the driving unit and controls a gain of the optical amplifier for each pulse by changing a pulse width of the pulsed drive current from driving unit so as to change the pulse width of the pumping pulsed light;
wherein the control unit is configured such that immediately after changing the state of the high power pulsed light generation device from an OFF state to an ON state, the pulse width of the pulsed light for pumping corresponding to a first pulse of the output pulsed light from the optical amplifier is longer than the pulse width of the pulsed light for pumping in a stable ON state of the optical amplifier; and
wherein the OFF state is a state in which the driving of the pump semiconductor laser is stopped and the high power pulsed light is not output from the optical amplifier, and the ON state is a state in which the driving of the pump semiconductor laser is started and the high power pulsed light is output from the optical amplifier.
2. The high power pulsed light generation device according to claim 1 ,
wherein the control unit is configured such that the absolute value of an adjustment width gradually decreases immediately after the change to the ON state when the difference between the pulse width of the pulsed light for pumping immediately after the change to the ON state and the pulse width in the stable ON state is defined as the adjustment width.
3. The high power pulsed light generation device according to claim 1 ,
wherein the control unit is configured such that a monitor that monitors the output pulsed light is installed in an emission side of the optical amplifier,
the monitor measures an amount of light received of the output pulsed light which is incident on the monitor, and
the amount of light received measured by the monitor is input to the control unit for the every high power pulsed light emitted from the optical amplifier to control the pulse width of the pulsed light for pumping according to the change of the amount of light received.
4. The high power pulsed light generation device according to claim 2 ,
wherein the control unit is configured such that a monitor which monitors the output pulsed light is installed in an emission side of the optical amplifier,
the monitor measures an amount of light received of the output pulsed light which is incident on the monitor, and
the amount of light received measured by the monitor is input to the control unit for the every high power pulsed light emitted from the optical amplifier to control the adjustment width according to the change of the amount of light received.
5. The high power pulsed light generation device according to claim 1 ,
wherein the optical oscillator is configured such that, immediately after changing the state of the high power pulsed light generation device from the OFF state to the ON state, the timing of the output of the pulsed light for pumping is adjusted to control the pulse width, a timing at which the pulsed light synchronized with the master clock signal is output is after a timing at which the output of the pulsed light for pumping is output.