DPSS laser driver

The driver designed for powering and control of Diode Pumped Solid State (DPSS) CW and QCW lasers.

The driver is enabling to execute a number of functions in a time:

• - provides with CW or QCW current the pumping Laser Diode Arrays;
• - generates sync pulses at any frequency in the range 1-50 kHz for activating the driver of A-O switch in CW pump mode;
• - generates sync pulses at any frequency in the range 1-1000 Hz for activating the driver of E-O switch in QCW pump mode;
• - generates signal open/close for EM shutter in the laser cavity;
• - provides control over real pump current in CW mode, and over amplitude, width and reprate of pump current pulses in QCW mode;
• - provides control over sensors status (for instance, flow and temperature of coolant, laser module temperature, etc.);
• - provides control over cooling laser system.

Technical parameters of the driver

Current control limits

in CW mode ……………………………… 10-60А

in QCW mode ………………………….. 20-180А (40-240А *)

pulse duration …………………………………….………….50-1000 us

repetition rate …………………………………….………….1-1000 Hz

Frequency limits of A-O switching ………………………….. 1-50 kHz

Frequency limits of E-O switching …………………... 1-1000 Hz

Power supply ……………………… ~220V+/-10%, 50-60Hz

Dimensions ……………………2U standard 842х88.4х360 mm

................................3U standard 842х132.5х360 mm

Working voltage on laser diodes 2U standard 24V

........................................... 3U standard 36V

With outward Ac/Dc convertor 2U standard up to 100V

PC connection ……………………. RS-232, USB, Ethernet*)

Example of 2U driver in QCW mode:

1000Hz, 180A, 250 us, voltage up to 24V

Front panel of the driver

The panel includes the following operating control:

1. POWER key – switches wall net voltage to the driver.

2. LOCK with 2 positions On and Off, the last of which prohibits the work of the driver.

3. Emergency key ABORT of immediate action, which cuts off the pump current and blocks the controller. The following work is possible only after switching off and then switching on the Power key.

4. EMISSION key switches on and off the laser radiation.

5. 40 – symbol 4-stroke liquid-crystal display.

6. SHUTTER key switches on and off the E-M shutter. When the shutter is switched on the green LED shines and lasing is blocked.

7. MENU key – entrance into section of device parameter tuning.

8. FUNCTION keys for choosing and saving parameter values.

9. < and > keys to decrease and increase parameter value.

Rear panel of the driver

The panel includes the following connectors and switches:

1. Socket for standard cable of wall net power supply 190-250 VAC, 50-60Hz (Power ~220V)

2. RS-232 connector

3. Ethernet connector (installed optionally)

4. USB connector

5. Pump current connectors to supply Laser Diode Arrays in the laser module

6. Connector for laser head Sensors (coolant flow, temperature, etc.)

7. Connector for Cooling System (Chiller)

8. Interlock Connector

9-12. BNC sockets for internal and external signals, controlling driver and other equipment operation:

Trig In – provides interruption of the driver operation (pause) in CW mode and external synchronization in QCW mode,

Trig Out 1 – 5V sync output, coinciding with the rising edge of current pulse

Trig Out 2 – 5V sync output, coinciding with the falling edge of current pulse

13. BNC socket Current Monitor – for monitoring the shape of actual current pulses though the Laser Diode Arrays

Structural scheme of the driver

1 – Driver/PC communication over RS-232, USB or Ethernet channels

2 – Driver/other equipment connection (chiller, laser head sensors and E-M shutter, sync and interrupting signals from other controllers and devices, monitoring Diode Arrays current, etc.)

3 – leads to Pump Diode Arrays in the laser module

AC/DC – converter with manually tuning output voltage within +/- 10%. The converter is being chosen based on particular number of Diode Arrays. Controlled AC/DC – converter automatically tuned by the Current Control Module Due to the fact that this driver is being built as a controlled source of voltage, but not of current, its efficiency is determined by performance index of AC/DC convertors, which typically reaches 80-85%. Low heat generation permits to use 2U housing for the device capable to deliver up to 600-700W of electrical power to Diode Arrays. With the additional external AC/DC converters the driver is сapable to deliver even more power.

Structural scheme of the laser

1. Leads of Laser Diode Arrays power supply

2. Control of E-M shutter operation

3. Signals from laser head sensors (coolant flow, temperature, etc.)

4. Signals of external interruption (Interlock) of the driver operation

5. Signals of alarm status of the cooling system sensors (for instance, pressure, coolant temperature and coolant flow)

The driver operates in 2 modes: local and remote. In the first case, all settings, including choice of executing program, correction of program parameters, analysis of the sensors status, etc. are being done from the front panel of the driver. In remote mode, the driver is being controlled from PC via serial channel RS-232 (or USB, or Ethernet) with the help of Universal terminal. For more details please apply to the Laser Driver manual.