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4308 LaserSource, 8A

How to Buy
4308 LaserSource, 8A

The 4308 LaserSource provides up to 8A of current, with excellent noise and accuracy specs. The 4308 is an excellent choice for high power fiber pigtailed devices and other applications requiring up to 8A. Like all 4300s, the 4308 is also available with optional Quasi-CW (QCW) mode.

Simple User Interface
The 4308’s user interface is remarkably simple… so easy to use, you’ll have it up and running in no time. Unlike other instruments which rely on 7-segment LED displays and a confusing array of indicators and buttons, the 4308 instead presents information on a high contrast VFD display in an easy-to-read format. The 4308 displays current, voltage, and photodiode current simultaneously… no need to toggle though the readings as you would on most instruments. Settings and error messages are in clear English, not cryptic codes and flashing status lights.

Optional Quasi-CW (QCW) Mode
The 4308 offers an optional QCW mode (see the 4308-QCW model), a feature not found in most other laser drivers in this price range. Many applications require the low duty cycle, high current pulses that QCW offers to manage thermal loading on the device. With rise times of less than 20µs, and pulse widths as narrow as 100µs, the 4308-QCW offers an effective and low-cost QCW solution.

  • 8A range
  • 0.5mA resolution
  • <60uA noise
  • USB and RS-232 interfaces





Standard Computer Interfaces
The 4308 includes both USB and RS232 computer interfaces, allowing for quick and easy connection to a PC for remote operation. In addition, the LaserSource’s command set is compatible with ILX and Newport controllers, allowing you to leverage any existing software you may have already developed.
                                    USB & RS232 Connectors.gif

Ground Loops Eliminated
Like all LaserSources, the 4308 includes isolated inputs and outputs. In technical terms, this means that every input and output signal is electrically isolated, so that offset voltages, ground connections, and AC noise will not “bleed” into other parts of the electronics. Even the photodiode input is fully isolated from the laser output, ensuring full isolation of the laser output. In practical terms, this means it’s impossible to create a ground loop through the LaserSource, a common problem in laboratory setups where several different instruments are used in the same test. No other driver on the market has this capability.

Analog Modulation
The 4308’s analog interface supports modulation rates up to 40kHz.



CW Mode Specifications

    Range (mA)

0 – 8000

    Resolution (mA)


    Accuracy (±[% set+mA])

0.05% + 1.6

    Stability (ppm, time)

< 10, 1 hour

    Temperature Coeff (ppm/°C)


    Noise/Ripple (μA rms, low BW)

< 60

    Transients (μA)

< 600

    Compliance Voltage (V)


    Modulation Bandwidth (kHz)


    Modulation Input Range

0 – 10V, 10kΩ

    Range (μA)

25 – 20000

    Resolution (μA)


    Accuracy (±[% set+μA])

0.05% + 2

    Stability (ppm, time)

< 200, 24 hours

    Temperature Coeff (ppm/°C)

< 200

    PD Bias (V)

0 to -5V, software programmable

    Range (V)

0 – 4

    Resolution (V)


    Setpoint Accuracy (±[% set+V])

0.05% + 0.005

    Measurement Accuracy (±[% reading+V])

0.05% + 0.004



    Current Limit Accuracy (mA)


    Voltage Limit Accuracy (±% FS)




    Display Type

2x20 VFD

    Laser Connector

DB-9, female


On LDD connector

    Computer Interface

USB 2.0 Full Speed (Type B),
RS-232 (DB-9, male)

    Input Power

100V / 120V / 230V, 50 / 60Hz

    Size (H x W x D) [inches (mm)]

3.47 (89) x 8.5 (215) x 12 (305)

    Operating Temperature

+10°C to +40°C

    Storage Temperature

-20°C to +60°C