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.

Model	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 Ripple^a	<1.0 µA	<0.2 µA	<1.5 µA	< 3 µA	<5 µA	<15 µA	<50 µA
Ripple^b	<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, 24hours^c	<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	±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
Operating Temperature	0 to 40 °C
Storage Temperature	-40 to 70 °C
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

All technical data valid at 23 ± 5 °C and 45 ±15% relative Humidity
^a 10 Hz to 10 MHz, rms, typ.

^b 50/60 Hz, rms, typ.
^c 0 - 10 Hz typ., at constant ambient temperature

LDC Front Panel

Click to Enlarge

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	11	Diode Polarization 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

Click to Enlarge

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	8
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	8	Laser Diode Anode (with Polarity Cathode Grounded - CG)
5	Ground for Pin 1	9	Not Connected

Laser Diode Connector

DB9 Female

Laser Diode Remote*

BNC

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

Modulation Input**

BNC

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

Control Output***

BNC

***Analog Control Output (0 ...±10 V)

Chassis Ground

4 mm Banana Jack

Laser Diode Controller Selection Guide

The table below is designed to give a quick overview of the key specifications for our laser diode controllers. For more details and specifications, or to order a specific item, click on the appropriate item number below.

Item #	Drive Current	Compliance Voltage	Modulation	Package
LDC200CV	20 mA	6 V	External	Benchtop
VLDC002	25 mA	5 V	Int/Ext	OEM
VITC002	25 mA	5 V	Int/Ext	OEM
LDC201CU	100 mA	5 V	External	Benchtop
LD2000	100 mA	3.5 V	External	OEM
LD2000R	100 mA	3.5 V	External	OEM
EK2000	100 mA	3.5 V	External	OEM
LDC202C	200 mA	10 V	External	Benchtop
TLD001	200 mA	8 V	External	T-Cube
IP250-BV	250 mA	8 V^c	External	OEM
LD1100	250 mA	6.5 V^c	--	OEM
LD1101	250 mA	6.5 V^c	--	OEM
EK1101	250 mA	6.5 V^c	--	OEM
EK1102	250 mA	6.5 V^c	--	OEM
LD1255R	250 mA	3.3 V	External	OEM
LDC205C	500 mA	10 V	External	Benchtop
IP500	500 mA	3 V	External	OEM
LDC210C	1 A	10 V	External	Benchtop
LDC220C	2 A	4 V	External	Benchtop
LD3000	2.5 A	--	External	OEM
LD3000R	2.5 A	--	External	OEM
LDC240C	4 A	5 V	External	Benchtop
LDC4005	5 A	10 V	Int/Ext	Benchtop
LDC4020	5 A	10 V	Int/Ext	Benchtop
Dual Temperature and Current Controllers
LDC1300B	1 A	5 V	--	OEM
ITC4001	1 A	>10 V	Int/Ext	Benchtop
ITC4005	5 A	>10 V	Int/Ext	Benchtop
ITC4020	20 A	>10 V	Int/Ext	Benchtop

^a Constant Current
^b Constant Power
^c When using a 12 V Power Supply

We also offer a variety of rack mounted laser diode current & temperature controllers (OEM Modules, TXP Rack Modules, PRO8 Rack Modules)

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Posted Comments:

Poster: bdada

Posted Date: 2012-05-17 15:38:00.0

Response from Buki at Thorlabs: Thank you so much for your feedback and suggestion. We agree that it would be helpful to make the modulation bandwidth more visible, especially since these Laser Diode controllers look alike but have different modulation bandwidths. We will look into offering an immediate and long term solution. Thank you again for sharing your thoughts. Please contact TechSupport@thorlabs.com if you would like to discuss this further.

Poster:

Posted Date: 2012-05-16 17:20:10.0

Please consider printing the modulation bandwidth on the back panel next to the control input, this would save some of us from wasting valuable time. I was using your LDC201CU and didn't realize the BW was just 0.2 KHz as i was familar with the LDC202 which has a 250 KHz BW, silly me i just assumed they would be the same.

Poster: hautlutao

Posted Date: 2012-01-10 15:54:47.0

Dear Mr. or Mrs. Could the LDC laser diode driver driven laser diode operating in pulsed mode ?

Poster: jvigroux

Posted Date: 2012-01-10 10:00:00.0

A response from Julien at Thorlabs: thank you for your inquiry! Yes the LDC200C series can be used also in pulsed operation when using the external modulation input.

Poster: jvigroux

Posted Date: 2011-12-13 12:23:00.0

A response from Julien at Thorlabs: Thank you for your feedback! We'll put the links to the required cables on this product page as well as on the product page of the TED200C.

Poster: rsavioli

Posted Date: 2011-12-13 10:44:09.0

Why don't you have any information pointing to the CAB400 and related interface cables on this page or any other LDC or TED pages, with the exception of the PRO8 stuff? I just spent 10 minutes looking for them and finally had to pull out a catalog.

Poster: bdada

Posted Date: 2011-10-03 09:23:00.0

Response from Buki at Thorlabs: Thank you for so much your feedback. Our design engineers will look into this issue and we will contact you to discuss what you can do to improve the feel or performance of the knob.

Poster: olsonaj

Posted Date: 2011-10-02 10:30:21.0

Have had this controller for a couple years. An issue I've had is the front current control knob is very loose, and makes it hard to tune the current precisely (esp. important for manually current-tuning the wavelength of a diode laser). Also, at times the knob seems "loose" and the current will jump around between different values. Perhaps this is a faulty connection? On future designs I recommend a sturdier current control knob.

Poster: bdada

Posted Date: 2011-04-08 14:50:00.0

Response from Buki at Thorlabs to Emmanuel: Thank you for your feedback, Emmanuel. We will contact you shortly to discuss your set up and verify the laser diode is connected properly to the driver.

Poster: emmanuel.vanbrackel

Posted Date: 2011-04-08 09:01:22.0

I have a big issue with this kind of driver. Up to now, I used a home-made driver that was built many years ago. Nevertheless, I needed a less noisy source, so I bought this. I tried to plug my laser diode (HL 6320G), following each documentation (of the diode, AG, following the pins correctly ; of the current controller, connecting the right pins to their right place, chose properly the polarity on the driver, set the limit for the current to 70 mA, put the knob to the left,...) : and when I push "laser on", when no current, its ok. But as soon as I get 0.1 mA, the open lights up, and no current anymore. I tried other cables configurations, verified that my diode works (with the old controller). Whats wrong ? Has anyone experienced that ? Bests

Poster: jhartmann

Posted Date: 2009-08-13 12:52:30.0

A response from Juergen at Thorlabs to joonggun.ha: This error message indicates a hardware failure. From experience it is known to us, that in 99% of such cases the reason for this failure is operation of the item at 230V AC while it was set to 100/115V AC. Of course, mains fuse blows, however during fuses reaction time damages to electronic circuitry may happen. After replacement of mains fuse and setting to correct AC, the unit switches on, but indicates only "Err.05", no operation is possible. The unit must be returned for repair to Thorlabs, this repair is NOT covered by warranty as the unit has been used inappropriate: We put an eyecatching yellow sticker accross the AC power connector on the rear panel, alerting the operator "Use correct voltage setting and fuse - see manual". So prior to apply AC voltage, this sticker must be removed. Please contact the Sales office, from where it has been purchased, for return instructions.

Poster: joonggun.ha

Posted Date: 2009-08-12 22:21:52.0

We have a litter LDC202C LD Controller. Today, one controller displyed an error message and did not work. The message is "Err.05". I recheck operation manual but could not find this error message. What is the problem? Please, answer ASAP.

Poster: juergen

Posted Date: 2008-07-23 10:49:09.0

Hi Ina, Thank you for your feedback. Manual and web specs are correct - LDC201CU is an ultra low noise driver. This is achieved by a low pass filter on the current output. Due this LPF, the max. modulation frequency in CC mode is 200Hz (-3dB, small signal) In VOL19, p.419, spec table, 200kHz is stated, which is wrong. We will correct that. Juergen Hartmann

Poster: ina.kinski

Posted Date: 2008-07-18 01:50:28.0

Hi, there is a typo both on this webpage and the operation manual that comes with this laser diode controller (p. 37): The small signal 3dB bandwidth (cc mode) goes up to 200kHz, not 200Hz. Thanks

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20 mA - 4 A Laser Diode Drivers

Features

Modes

Controller Use

Protection Features

Connection Cables

LDC Front Panel

LDC Back Panel

Laser Diode Connector

Laser Diode Remote*

Modulation Input**

Control Output***

Chassis Ground

Laser Diode Controller Selection Guide