The 4205 LaserSource is our most popular laser driver in the 4200 Series, offering an excellent combination of low noise, accuracy, and resolution. The 4205 will work well in low power pump lasers, high power LEDs, and other applications requiring up to 500mA of drive current.
Simple User Interface
The 4205’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 4205 instead presents the information on a high contrast VFD display in an easy-to-read format. The 4205 displays current, voltage, and photodiode current simultaneously… no need to toggle though the readings like on most instruments. Settings and error messages are in clear English, not cryptic codes and flashing status lights.
Programmable PD Bias Voltage
Unlike other laser drivers, the 4205 includes a software programmable PD bias voltage, from 0 to -5V, so selecting your bias voltage has never been easier. Simply adjust the voltage in the user menu or via a software command… no more fumbling around with a DMM and screwdriver to adjust the trim pot.
- 500mA range
- 0.1mA resolution
- <4uA noise
- USB/RS-232 interfaces
Standard Computer Interfaces
The 4205 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.

Ground Loops Eliminated
Like all LaserSources, the 4205 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 4205's analog interface supports modulation rates up to 250kHz.
Specifications
CW Mode Specifications |
|
| LASER CURRENT | |
| Range (mA) |
0 – 500 |
| Resolution (mA) |
0.1 |
| Setpoint Accuracy (±[% set+mA]) |
0.05% + 0.1 |
| Measurement Accuracy (±[% reading+mA]) |
0.05% + 0.2 |
| Stability (ppm, time) |
< 10, 1 hour |
| Temperature Coeff (ppm/°C) |
50 |
| Noise/Ripple (μA rms) |
< 4 |
| Transients (μA) |
< 100 |
| Compliance Voltage (V) |
7 |
| Modulation Bandwidth (kHz) |
250 |
| Modulation Input Range |
0 – 10V, 10kΩ |
| PHOTODIODE CURRENT | |
| Range (μA) |
5 – 5,000 |
| Resolution (μA) |
0.1 |
| Setpoint Accuracy (±[% set+μA]) |
0.05% + 1 |
| Measurement Accuracy (±[% reading+μA]) |
0.05% + 1 |
| Stability (ppm, time) |
< 200, 24 hours |
| Temperature Coeff (ppm/°C) |
< 200 |
| PD Bias (V) |
0 to -5V, software programmable |
| LASER VOLTAGE | |
| Range (V) |
0 – 7 |
| Resolution (V) |
0.001 |
| Setpoint Accuracy (±[% set+V]) |
0.05% + 0.005 |
| Measurement Accuracy (±[% reading+V]) |
0.05% + 0.001 |
| Stability (ppm, time) |
< 50, 1 hour |
| Temperature Coeff (ppm/°C) |
< 100 |
LIMITS |
|
| Current Limit Accuracy (mA) |
5 |
| Voltage Limit Accuracy (±% FS) |
2.5% |
GENERAL |
|
| Display Type |
2x20 VFD |
| Laser Connector |
DB-9, female |
| Computer Interface |
USB 2.0 Full Speed (Type B), RS-232 (DB-9, male) |
| Input Power |
100V / 120V / 230V / 240V, 50 / 60Hz |
| Size (H x W x D) [inches (mm)] |
1.82 (47) x 8.5 (215) x 11.13 (283) |
| Operating Temperature |
+10°C to +40°C |
| Storage Temperature |
-20°C to +60°C |