A low jitter variable delay generator for regenerative amplifier in a table top terawatt femto second laser system

This paper describes the design and development of a pulse selector circuit, two different low cost techniques for generation of low jitter variable delays and a high band width line driver for use in the regenerative amplifier stage of a table top Terawatt femto second laser chain. The pulse selector stage selects one pulse from a high frequency laser oscillator, injects it into the regenerative amplifier and ejects it after a preset delay. Two different schemes for the delay generator described here are based on the IC AD 9501 and ECL mono shots. These can provide variable delay in the range of 2.5-800 ns. Jitter in the set delay for the circuit based on ECL mono shot is found to be 800 ps. Whereas, jitter for the circuit based on AD9501 is dependent on the set delay and varies between 500 ps to 2.2 ns over the entire delay range of 2.5-800 ns.