Qioptiq DIV 20 User manual

Pulse Amplifier DIV 20
Instruction Manual
03/2016
QIOPTIQ Photonics GmbH & Co. KG
Hans-Riedl-Str. 9
D-85622 Feldkirchen
Germany
Tel.: [phone]
Fax: [phone]

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1. Safety remarks
In order to avoid unwanted damage or hazards, please read this instruction
manual carefully before operation.
The DIV 20 has to be operated by trained personel only !
The pulse amplifier DIV 20 is specially designed to drive capacitve loads with
an extremely fast rise-time and high repetition rate. A high voltage of up to
600V can be present at output sockets (Pulsausgang) and (Offsetausgang) of
the driver and the maximum current may be as high as 8 A. Never touch any
plugs when the modulator cable is connected to the DIV 20. A voltage up 600 V
may be accessible in case of a damage.
The connection to and operation of the protective ground has to be
ensured always !
Switch on the DIV 20 only after the cable connection between modulator and
driver is established. Before connecting the cable, make sure that the line
switch (S4) is off. Before disconnecting the cable, the DIV 20 must be in the off
position for at least 5 minutes, in order to guarantee that the grounding
capacitors are completely discharged.
For safety reasons we recommend establishing the following settings prior to
switching on:
1) control knob DC-Offset (PO) to minimum (fully counter clock-wise)
2) mode switch (S2) to LOW.
Any contact with water has to be avoided (IP20-class product)!
Do never operate the DIV 20 with opened housing !
Rapairs have to be done by qualified representatives of the manufacturer
only !
2. General remarks
The pulse amplifier DIV 20 is a digital driver for electro-optic modulators (EOM).
It transforms a low voltage (TTL) input signal into a high voltage output with an
extremely fast rise-time. The amplitude of the high voltage pulses is user-
controllable. A variable offset voltage permits selection of the optimum working
point. Signal voltage and offset voltage work on separate electrodes of the
modulator. User controllable functions cable connectors and adapters are
designed for use of the DIV 20 with the laser modulators LM 0202 and LM 13.

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Other loads can be switched by the addition of the DIV 20, if the maximum load
(as specified under section 6 of this manual) will not be exceeded.
3. Description of the control and display elements
Legend
Description
Display
Display for pulse or offset voltage
S1
Switch DIV 20 Display to show pulse or offset voltage
the green LEDs L1,L2 indicate the displayed voltage
S2
Mode switch: green LED L5/L6/L4 indicates the operation
mode
S3
Impedance switch for the input signal (50/600)
S4
Main Power Switch
L3
Temp/Alarm
Red LED on: thermal overload
Red LED flashing: current overload
L7
Indication of external pulse voltage control
Red LED on: only external control using the 25-pin Sub-D-
Connector
L8
Indication of external offset voltage control
Red LED on: only external control using the 25-pin Sub-D-
Connector
PO
Control knob: DC-offset voltage
PP
Control knob: pulse voltage
Pulseingang
“Input TTL” socket: signal
Pulsausgang
Output socket: pulse voltage
Offsetausgang
Output socket: offset voltage

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Fig. 1: Front panel of DIV 20 with control and display elements

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4. Operation
This description explains operation of the DIV 20 as driver for the laser
modulator series LM 0202 or LM 13 in the light chopper mode. For these
modulators a special cable and an adapter are included with the DIV 20.
Operation of the DIV 20 with other modulators or in other modes is similar.
The DIV20 has to be switched off for any connecting procedures.
Begin setup (see Appendix A) by connecting the special adapter with the
modulator, such that the banana plugs are fully inserted (step 1). For the
completion of the adapter connection, the two housing screws of the plug have
to be screwed into the modulator housing (step 2). Then connect the special
plug of the cable´s modulator-side to the adapter (step 3) and finally the cable´s
input side (2 triaxial plugs) to the output sockets (Offset) and (Pulse) of the DIV
20 as depicted in Appendix B. Also connect the ground Banana-plug to the
corresponding Banana-plug at the DIV 20.
If you want to use another cable instead of the included special cable, please
note that cable length must be less than 0.5 m with a capacity of less than 40
pF/m. Otherwise reduction of the specifications is possible. The connected
system (including the cable) must have a sufficient isolation strength to
withstand the maximum output voltage. Also EMC-qualities of the new cables
would have to be proven by the applicant to justify a CE-certification.
Connect your TTL-signal generator with “Input TTL” socket and attach the
Ferrite (delivered with the DIV 20) to the cable used for the connection. For best
EMC-performance also use Ferrites on the modulator-cable (Appendix C).
Switch on the DIV 20 using the power switch (S4): the line control LED
indicates power on.
The DC-Offset knob (PO) controls the offset voltage within the range 0 V to
+600 V. This permits compensating possible double refraction induced
birefringence of the modulator and choosing the optimum working point.
Before setting the offset voltage, the modulator should have reached thermal
equilibrium with the environment. The offset voltage chosen is such that mini-
mum light intensity is achieved behind the modulator. Make sure that the mode
switch (S1) is set to the LOW position. In order to reach optimum conditions,
the modulator must be correctly aligned as well. Please refer to the manual
laser modulator LM 0202.
Finally, by optimizing the setting of offset and pulse voltage, the light intensity
will be minimum in the LOW position of the mode switch (S2) and maximum in
the HIGH position. Further increase of the pulse voltage will only reduce the
maximum light intensity. Once correctly adjusted, the pulse voltage does not
need any further readjustment. Changing temperatures, on the other hand,
might require readjustment of the offset voltage.
Once correct values for pulse and offset voltages are found, set the mode
switch (S2) to the PULSE position. Set the output voltage of your signal
generator such that the DIV 20 is reliably triggered according to +5 V TTL-

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signal. The output impedance of the signal generator must be sufficiently low to
drive the input of the DIV 20 (see section 7. specifications). The input
impedance of the DIV 20 can be switched to 50 or to 600 . In the case of
narrow pulses combined with high repetition rates, we recommend choosing 50
for the input impedance. Make sure that the function generator also provides
50 output impedance. With the 50 connection, reflections in the connector
cable are avoided. Such reflections in the connector cable can cause faults in
the signal trigger. For the special version DIV 20 (600 Ohm) the input
impedance is fixed at 600 Ohm and the impedance switch is missing.
Additonal important remarks
Mistakes in the handling of the DIV 20 are preserved by the display of nearly all
operation modes via LEDs on the front panel. The red LEDs are of premium
importance. If the TEMP is on, then an overload condition or a fault in
connection is indicated. The red LEDs EXTERN indicate that the DIV 20 is set
for external control of the offset voltage (LED above the DC-offset knob is on )
and/or of the pulse voltage (LED above the pulse voltage knob is on).
The TEMP LED indicates an overload condition of the DIV 20. The flashing
LED indicates a current overload. To re-receive a signal voltage at the output
socket, either the pulse voltage has to be set to the minimum value or the
frequency has to be reduced. The frequency has to be reduced until the current
overload is switched off. Instead of the reduction of the pulse voltage, another
possible way to switch off the current overload, is to set the mode switch (S2) to
the LOW position. After switching the mode switch again to the HIGH position,
the signal voltage is again available on the output socket.
The constant shining TEMP LED indicates an thermal overload of the DIV 20
amplifier. If the LED is on, no voltage is supplied to the output socket for the
pulse voltage. After a recovery time of ~20 seconds, the output pulse voltage is
re-received automatically.
In the PULSE position of the mode switch (S2), the light intensity follows the
pattern of the input signal. Intermediate intensity levels (grey scales) cannot be
switched: the DIV 20 is a pure digital (on/off) driver.
The safety of the complete measurement system in which the DIV20 is
integrated, is the responsibility of the installer of the system.
5. Remote control
Pulse voltage and offset voltage can be controlled externally. This permits, for
instance, installing automatic temperature drift compensation or laser power
drift compensation. For external control, the 25-pin Sub-D Connector on the
back panel of the DIV 20 should be used (see chapter 10).

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6. Inverted intensity pattern
It is extremely easy to invert the generated pulse pattern: Set the mode switch
(S2) to the LOW position and adjust the offset, such that maximum light
intensity is given. Then set the mode switch (S2) to the HIGH position and
adjust pulse voltage, such that minimum intensity is given. In the PULSE
position of the mode switch (S2), now the light intensity pattern is inverted.
7. Maintenance
Replace the fuse only with the correct rating:
2x 250V/4A 5x20mm SLO-BLO
Replace the power cord:
The power cord specification must match the power requirements of the DIV20.
8. Ventilation
For proper operation and protection of the Device it is important that the
ventilation passages located at the front and rear of the device are not
obstructed from free airflow.
9. Specifications of the DIV 20
The DIV20 is intended for in-door use at maximum altitude of 2000m only in a
dry and clean environment (pollution degree <2). A special cable with
connectors suitable for the LM 0202 or LM 13 series modulators is included.
The technical specifications of the DIV 20 listed below are obtainable for a
connected capacity of 80 pF, using the delivered special cable for connection.

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Specification
Description
Signal Input
Input Impedance
50 / 600 adjustable
Input voltage Low
0V .. 0.4V
Input voltage High
2.4V .. 5.5V
Pulse width
>30 ns
AC Power
115V/230V (±15%), 50/60Hz, 400W
overvoltage category II,
Output voltage
Pulse output voltage
0V .. 590V
Maximum pulse output current
<8A
Output impedance
50 
Rise time (10% - 90%)
Typ. 23-27ns (@ 590V)
Typ. 20-25ns (@ 350V)
Voltage stability
< 6%
Input-output delay
<150 ns
Offset output voltage
0V .. 590V
Maximum offset output current
<1.5 mA
Operation environment
Temperature
10 .. 35°C
Humidity
< 80%RH
Pysical Features
Dimensions
260 (W) x 155 (H) x 330 (D)
(dimensions in mm)
Weight
9.5 kg
Connectors
Pulse output Voltage
SHV- BNC 50 
Offset output Voltage
SHV- BNC 50 
Pulse input Voltage
BNC 50 
External Control
SubD 25p female

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Load diagram
Fig. 2: Dependence of the maximum frequency on the applied pulse voltage
10. Interface for external control
The external control is possible using the 25-Pin-Sub-D connecter in the rear
panel of the DIV 20. The trigger signal is TTL.
Pin assignment
Pin
Description
1
GND
2
Input control voltage for the pulse voltage
0 -10 V DC = 0 - 600 V pulse voltage
input resistance ca. 50 k
3
adjustment of pulse voltage
0 = internal
1 = external via PIN 2
4
output for offset voltage measurement
(0 - 4 V 0 - 600 V)
5
output for pulse voltage measurement
(0 - 4 V 0 - 600 V)

1
0
6
+15 V
7
NC
8
GND
9
temperature control
0 = normal
1 = thermal overload
alternate 0/1 = output current overload
10
+5 V (< 100 mA)
11
input control voltage for the offset voltage
0 - 10 V DC 0 - 600 V pulse voltage
input resistance ca. 50 k
12
adjustment of offset voltage
0 = internal
1 = external via PIN 11
13
NC
14
PIN 14
PIN 15
0
0
internal control
0
1
external control: signal
1
0
external control: low
1
1
external control: high
15
16
NC
17
NC
18
GND
19
GND
20
GND
21
GND
22
GND
23
connection with PIN 10 for external control
24
GND
25
GND
11 Waste treatment
This Qioptiq product may not be disposed in the normal waste
disposal!
If this Qioptiq product is no longer used and should be disposed,
please contact Qioptiq or your nearest dealer for further
information

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Appendix A:
Fig. 3: Connecting the Adapter

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Appendix B:
Connecting the special cable to the DIV 20 Output Socket:
1. Plug 1 marked as “Pulse” has to be connected to the Pulse-Output Socket. See Fig.4
below.
2. Plug 2 marked as “Offset” has to be connected to the Offset-Output Socket. See Fig.4
below.
3. The Banana-plug of the cable has to be connected to the Banana-Socket at the DIV 20
front-side. See Fig. 4 below.
Fig. 4: Connecting the Modulator-cable to the DIV 20 and ferrite to Pulse-Input

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Appendix C:
Using the Bulk-Ferrite:
4 pcs Ferrite are shipped with the DIV 20 driver. Please assemble them to the
cables in the following way:
1. Ferrite No. 7427154 has to be mounted to the cable plugged to the Pulse-Input-TTL of
the DIV 20. The Ferrite should be placed close to the “Pulse”-Input-TTL (max. 30cm
distance). In case a thin cable is used there may be a loop (loop diameter <10cm) to
fix the Ferrite-position (see Fig.4).
2. For best EMC-performance please mount the 2 Ferrites No. 74271221 and 1 Ferrite
No. 74271131 to the special (3-wire) cable close to the output-side of the DIV 20
special cable (distance from the output-plug should be less than 35 cm). Although
their order is not relevant, we suggest arranging them as depicted on Fig.5. Then the
Ferrites maximum distance from the load (here a LM0202 type modulator) is fixed by
the small Ferrite.
Fig. 5: Connecting Ferrites to the Modulator-cable