Research On Intelligent Control Used In Laser Pulse Shaping

The drive facility is the key technical step for controlling the inertial confinement fusion(ICF). The present of integrated optics new concept make the laser pulse shaping available.Electrical pulse shaping is the key technical in laser pulse shaping that integrated optics conceptwas adopted.An intelligent control system was developed to achieve the goal that making the shapingelectrical pulse arbitrary waveform generator (AWG) provided precise. The intelligent controlsystem consists of high-speed data acquisition and data processing system.The main purpose of the high-speed data acquisition system is to obtain the shape ofshaping electrical pulse. The A/D converter MAX105with sampling rate of800Msps is the keyfacility in the high-speed acquisition system. However the high-speed acquisition system requiressampling rate of1.6Gsps, then, two pieces of MAX105was fabricated based on parallelsampling technique in this system to achieve the1.6Gsps sampling rate. The thesis in this partfocused on the following issues: high-speed analog to digital converter, clock signal processingand also the high-speed data transmission. However some points about print circuit board (PCB)design were deeply discussed, such as PCB stack-up, signal crosstalk, delay and signal reflection.The point of reference ground was mentioned at the last of this part.TheAWG is based on Gallium-Arsenide Field Effect Transistor (GaAs FET) set whichhas a good ability of on-off switching and generating voltage-controlled current. Theultra-narrow pulse triggers the GaAs FETs and multiple negative pulses are generated. Thedifferent time delay for each pulse is introduced by transmitting it through analog time delay wire.Finally we have a micro-strip line to couple the pulses and get the overlapped pulse shape. Thegate bias on FET determines the magnitude of pulse, so we can get the arbitrary pulse byoverlapping the multiple pulses with various magnitudes and time delays. To satisfy high amplitude requirement on electrical pulse for ICF system, an ultra-broad bandwidth voltagetunable amplifier is applied to the output signals and the pulse amplitude is adjustable.The FPGAis adopted in data processing after signal acquisition. It processes the sampledsignal and given the feedback signal to the input pins of the AWG. Thus, the output ofthe AWGcan be adjusted dynamically. This process repeated until the shaping electrical pulse is consistentwith the value we expected.