Quantum Instruments Cascade Laser Starter Kit manual QCL pulser switching unitLDD100

Starter Kit Instruction Manual Description 20

4.5QCL pulser switching unit(LDD100)

4.5.1Description

The switching unit is based on dedicated power MOS-FETS with up to 30A current compatibilities and 60V. In addition, the circuit is limited in power dissipation by the cooling of the unit. During op- eration, the temperature of the case should not ex- ceed 60C. While powering usual QC diodes, these limitations are never reached because the laser has usually much lower power ratings.

! WARNING !

An important feature of this unit is that both lines going to the laser are ”HOT”, i.e. have a postive voltage respective to the case. this feature should be kept in mind when de- signing the laser holder. This one should be insulated and have a low capacitance(< 100pF) towards the ground.

The QCL pulse switching unit is composed of the following connectors:

(1)Low impedance connector

(2)Drive cable connector

(3)Monitoring BNC connector

4.5.2Specifications

Voltage : . . . . . . . . . . . . . . . . . . . . . . max 60 VDC

Current : . . . . . . . . . . . . . . . . . . . . . . max 30 ADC

Repetition rate : . . . . . upto 1MHz, limited by average current

Rising/falling edge: . . typical 8ns (max 12ns)

Minimum pulse width: . . . . 16ns, typical 20ns

Maximum pulse width: 1µs, limited by power supply

Support power: . . . . . . . . . . . . given by TPG128

Trigger IN: . . . . . . . . . . . . . . . . . . . . . . . . TTL 50Ω

Propagation delay: . . . . . . typical 35ns <40 ns

Size: . . . . . . . . . . . . . . . . . . . . . 90 x 130 x 50 mm3

! WARNING !

The connection between the laser and the QCL pulse switching unit is floating. It must not be connected with the ground.

2

3

Z50

Ohm

A/V,

20

Input

12V

60V

Monitor

supply

Max

Power

control

Voltage

Current

High

hi +

Bottom

to

top, on

Output

Pulseconnected

LDD

100

1

Fig.9: QCL pulser switching unit front and rear view