Pockels Cell Drivers - FDM Series Pulse Generators

FDM modular type drivers have a compact size which makes it easy to place them very close to a Pockels cell. The connection is made by short 2-10 cm long wires. Such variant of connection allows significantly lowering of the average power of the driver while keeping operating voltage and pulse duration. Typical dimensions of FDM series pulsers are 120x60x40 mm.

FDM series can include any combination of subvariants:
W	capability of paired operation into a single Pockels cell
K	high contrast output for high-quality optical output
U	ultra-compact drivers with uncompromised performance and dimensions of only 60x60x20 mm

Most of modifications of this series are forming bell shaped voltage pulses with the pulse duration at half maximum of 3-6 ns and the amplitude of 5-14 kV.

The drivers are manufactured with an assumption that the Pockels cell capacitance is 4-6 pf. For better matching and reduction of oscillations it is recommended to connect a 2-3 kOhm load in parallel to a Pockels cell.

Maximum PRF of drivers of FDM series is 100 kHz. At the PRF higher than 10 kHz it is necessary to use forced air cooling of a driver housing and integrated heat sinks. At PRF above 50 kHz a liquid cooling becomes more efficient.

Modular drivers require DC power input of 250-500 V and triggering pulses with the amplitude of 20-30 V, rise time of 10-20 ns and pulse duration of 100 ns. The input power at 5 kHz is about 20 W. The output pulse amplitude is adjusted in range of 50-100% by change of the input voltage between 250 and 500 V.

Delay between the external triggering pulse and the output high voltage pulse is about 200 ns. Jitter of this value is only 20-30 ps, which allows precise timing.

Together with drivers FID GmbH offers its own DC/DC power supply-converter with the input voltage of 24 V and the output voltage of 500 V. Such converters have a triggering pulse amplifier which allows using standard TTL 5V triggering pulses.

Reference Models

Sample pulse shapes

	Maximum amplitude	Rise time	Fall time	Pulse width
				@ 90%	@ 50%	@ 10%
	7,8 kV	2,3 ns	2,7 ns	1,7 ns	4,1 ns	7 ns
	8 kV	3,3 ns	2,7 ns	2,2 ns	5,1 ns	7,9 ns
	10 kV	2,2 ns	3,8 ns	2,2 ns	5,7 ns	8,5 ns
	10,8 kV	4 ns	3,6 ns	2,6 ns	6,3 ns	10,2 ns
	12,6 kV	3,6 ns	3,2 ns	2,3 ns	5,6 ns	9 ns