Features
- Extremely Low Noise (LDC201CU 0.2 μA)
- 5-Digit LED Display
- Analog Control Input and Output
- Reliable Laser Diode Protection
- Operates With All Polarities of Laser Diode and Photodiode
- Seven Models With Laser Current Ranges From 20 mA to 4 A
- Certificate of Calibration and Test Report Included
The laser diode controllers in the LDC200C series all provide features that ensure outstanding performance. There are seven models with different current ranges, each configured to provide optimal performance for their particular application. Every unit ships with a certificate of calibration as well as a full test report. Please refer to the Specs tab and the Selection Guide tab for an overview of the products.
Modes
With the laser diode controllers of the LDC200C series, laser diodes can be driven in constant current (CC) or constant power (CP) mode. All laser diode and photodiode configuration types are supported. The laser diode is always driven with respect to ground. In comparison to driver designs that require a floating ground, this grounded operation of the laser diode offers advantages regarding noise, transient suppression, and stability.
Constant Current
In CC mode, the current to the laser is held precisely at the prescribed level. This mode is used when the lowest noise and highest response speed is required. Most applications in this mode require stabilizing the temperature as well. We offer two lines of temperature controllers, the TED200C for up to 12 W and the TED4015 for up to 225 W.
Constant Power
In CP mode, the internal photodiode integrated into most laser diode packages is used to actively stabilize the laser's output power, which is adjusted by a feedback circuit. An adjustment of the full scale photodiode current in CP mode is provided in order to compensate for the differences in the photodiode currents between different laser diodes.
Controller Use
Intuitive User-Friendly Operation
Independent of the selected operating mode, the 5-digit LED display can show the laser current, the photodiode monitor current, or laser current limit. It can also display the optical power (in mW). The power readout can be calibrated to the responsivity of the monitor photodiode by adjusting a front panel trim potentiometer. In many applications, the aforementioned benefits eliminate the need for a separate optical power meter.
Additional Rear Panel Controls
Available for use at the rear of the unit are: a modulation input for laser current or power (which can be used to pulse the laser diode output), a control output proportional to the laser current, and a TTL input for remote laser on/off.
Protection Features
Current Limit
A precisely adjustable current limit ensures that the maximum laser current cannot be exceeded. Thorlabs has intentionally provided limited access to this feature to prevent accidental adjustment. An attempt to increase the laser drive current above the pre-set limit will result in a visible and short audible indicator. Even when utilizing the external modulation feature, the current limit set-point cannot be exceeded.
Current Source
If the connection between the current source and laser diode is interrupted, the current source automatically switches off the current output. The open current circuit condition is indicated by the LED "OPEN" and a short acoustic warning. The separate laser ON key switches the laser current on and off. When switched off, an electronic switch within the LDC200C short circuits the laser diode for added protection. After being switched on, a soft start ensures a slow increase of the laser current without voltage peaks. Even in the case of line failure, the laser current remains transient-free. Voltage peaks on the AC line are effectively suppressed by electrical filters, shielding of the transformer, and careful grounding of the chassis.
Connection Cables
A CAB400 is required to connect the LDC200C series laser diode controllers to a Thorlabs' Laser Diode Mount. One cable is included with each laser diode controller, it has a length of 1.5 m. Additional cables can be ordered below.
Item # |
LDC200CV |
LDC201CU |
LDC202C |
LDC205C |
LDC210C |
LDC220C |
LDC240C |
Current Control (Constant Current Mode) |
Control Range |
0 to ±20 mA |
0 to ±100 mA |
0 to ±200 mA |
0 to ±500 mA |
0 to ±1 A |
0 to ±2 A |
0 to ±4 A |
Compliance Voltage |
>6 V |
>5 V |
>10 V |
>10 V |
>10 V |
>4 V |
>5 V |
Resolution |
1.0 µA |
10 µA |
10 µA |
10 µA |
100 µA |
100 µA |
100 µA |
Accuracy |
±20 µA |
±50 µA |
±100 µA |
±0.5 mA |
±1.0 mA |
±2.0 mA |
±4.0 mA |
Noise Without Ripplea |
<1.0 µA |
<0.2 µA |
<1.5 µA |
<3 µA |
<5 µA |
<15 µA |
<50 µA |
Rippleb |
<0.5 µA |
<0.5 µA |
<1.5 µA |
<2 µA |
<3 µA |
<5 µA |
<8 µA |
Transients (typ.) |
<10 µA |
<10 µA |
<0.2 mA |
<0.5 mA |
<1 mA |
<2 mA |
<4 mA |
Drift, 24hoursc |
<1 µA |
<2 µA |
<3 µA |
<10 µA |
<20 µA |
<100 µA |
<200 µA |
Temperature Coefficient |
<50 ppm/°C |
Current Limit |
Setting Range |
0 to >20 mA |
0 to >100 mA |
0 to >200 mA |
0 to >500 mA |
0 to >1 A |
0 to >2 A |
0 to >4 A |
Resolution |
1 µA |
10 µA |
10 µA |
10 µA |
100 µA |
100 µA |
100 µA |
Accuracy |
±50 µA |
±200 µA |
±500 µA |
±1.5 mA |
±2.5 mA |
±5 mA |
±10 mA |
Power Control (Constant Power Mode) |
Photocurrent Control Range |
5 µA to 2 mA |
25 µA to 10 mA |
50 µA to 20 mA |
Photocurrent Resolution |
0.1 µA |
1 µA |
1 µA |
Photocurrent Accuracy |
±2 µA |
±10 µA |
±20 µA |
Analog Modulation Input |
Input Resistance |
10 kΩ |
Small Signal 3dB Bandwidth, CC Mode |
DC to 100 kHz |
DC to 0.2 kHz |
DC to 250 kHz |
DC to 150 kHz |
DC to 100 kHz |
DC to 50 kHz |
DC to 30 kHz |
Modulation Coefficient, CC Mode |
2 mA/V ± 5% |
10 mA/V ± 5% |
20 mA/V ± 5% |
50 mA/V ± 5% |
100 mA/V ± 5% |
200 mA/V ± 5% |
400 mA/V ± 5% |
Modulation Coefficient, CP Mode |
0.2 mA/V ± 5% |
1 mA/V ± 5% |
2 mA/V ± 5% |
Laser Current Monitor Output |
Load Resistance |
>10 kΩ |
Transmission Coefficient |
500 V/A ± 5% |
100 V/A ± 5% |
50 V/A ± 5% |
20 V/A ± 5% |
10 V/A ± 5% |
5 V/A ± 5% |
2.5 V/A ± 5% |
General data |
Safety Features |
Interlock, Laser Current Limit, Soft Start, Short Circuit when Laser Off, Open Circuit Detection, Over Temperature Protection |
Display |
LED, 5 Digits |
Connector for Laser, Photodiode, Interlock & Laser On Signal |
9-pin D-Sub Jack |
Connectors for Control Input / Output |
BNC |
Chassis Ground Connector |
4 mm Banana Jack |
Line Voltage / Frequency |
100 V, 115 V, 230 V +15% –10% each / 50 to 60 Hz |
Maximum Power Consumption |
20 VA |
20 VA |
25 VA |
30 VA |
40 VA |
60 VA |
100 VA |
Mains Supply Overvoltage |
Category II (Cat II) |
Operating Temperature |
0 to 40 °C |
Storage Temperature |
-40 to 70 °C |
Relative Humidity |
Max. 80% Up to 31 °C, Decreasing to 50% at 40 °C |
Pollution Degree (Indoor Use Only) |
2 |
Operation Altitude |
<2000 m |
Warm-up Time for Rated Accuracy |
10 min |
Weight |
<3.1 kg |
<3.3 kg |
Dimensions (W X H X D) without Operating Elements |
146 x 66 x 290 mm³ |
Dimensions (W X H X D) with Operating Elements |
146 x 77 x 320 mm³ |
LDC Front Panel
Callout | Connection | Callout | Connection |
---|
1 | 5-Digit LED Display | 9 | Display Indicators |
2 | Display Units | 10 | Up/Down Display Select |
3 | Interlock Indicators | 11 | Diode Polarization Indicator |
4 | Laser Status Indicator |
5 | Laser Current On/Off Switch | 12 | Output Mode Indicator |
6 | Display Adjustment Knob | 13 | Diode Polarization Select |
7 | Supply Power Switch | 14 | Output Mode Select |
8 | Current Limit and Power Calibration Pots | 15 | Photodiode Current Range Pot |
LDC Back Panel
Callout | Connection | Callout | Connection |
---|
1 | TTL Input "LD REM" 0 to 5 V | 6 | Connector "LD OUT" for LD, PD, Interlock, & Status LED |
2 | Modulation Input / Analog Control Input "MOD IN", -10 to +10 V | 7 | Serial Number of the Unit |
3 | Analog Control Output "CTL OUT", -10 to +10 V | 8 | Indicator / Switch for Line Voltage (Included in Fuse Holder) |
4 | Cooling Fan |
5 | 4 mm Banana Jack for Chassis Ground | 9 | Power Connector and Fuse Holder |
Pin |
Connection |
Pin |
Connection |
1 |
Interlock and Status LASER ON/OFF |
6 |
Not Connected |
2 |
Photodiode Cathode |
7 |
Laser Diode Cathode (with Polarity Anode Grounded - AG) |
3 |
Laser Diode Ground |
8 |
Laser Diode Anode (with Polarity Cathode Grounded - CG) |
4 |
Photodiode Anode |
5 |
Ground for Pin 1 |
9 |
Not Connected |
Laser Diode Connector

Laser Diode Remote*

*TTL Input
(0...+5 V)
Modulation Input**

**Analog Control Input
(-10 V ...10V)
Control Output***

***Analog Control Output
(0 ...±10 V)
Chassis Ground
