QCL Current/TEC Controller


High-Power Current/TEC Controller for QCLs

  • 20 V Compliance Voltage Designed to support QCL Lasers
  • Supports Laser Currents up to 5 A
  • Provides TEC Currents up to ±15 A
  • 0.002°C Temperature Stability over 24 hrs


  • 20 V Compliance Voltage Supports High-Power QCLs
  • Drive Lasers with Operating Currents ≤5 A and Voltages ≤20 V
  • Capable of Driving LEDs for Continuous Wave (CW) or Quasi-CW Operation
  • Active Power Management for Efficient Operation
  • Excellent Temperature Stability: 0.002 °C (24 hrs)
  • Digital PID Control with Separate P, I, D Settings
  • Auto PID Tuning Function
  • Adjustable Temperature Sensor Offset
TEC Features
Compatible Temperature Sensors
  • NTC Thermistors
  • Current Temperature Sensors
  • Voltage Temperature Sensors
  • Platinum RTD Temperature Sensors
TEC Security Features
  • Adjustable TEC Current Limit
  • Adjustable Temperature Limits
  • Temperature Window Protection
  • Fault Connection and Sensor Alarm
Laser Controller Features
Compatible Optical Detectors
  • Photodiodes
  • Thermopiles
  • Common Sensor Amplifiers
  • Power Meters with Voltage Output
Laser Diode Protection Features
  • Adjustable Laser Current Limit
  • Adjustable Laser Power Limit
  • Laser Over Voltage Protection
  • Over Temperature Protection

Thorlabs' ITC4005QCL Combined Laser Current and TEC Controller is designed with a 20 V compliance voltage to support our high-power Quantum Cascade Lasers (QCLs). The device combines the functionality of an LDC4000 series current controller and a TED4015 temperature controller into a single device. The ITC4005QCL provides precise, stable current for lasers with a maximum operating current of 5 A and excellent temperature stabilization to within 0.002 °C over a period of 24 hrs. It is our only controller that supports our entire selection of mid-IR lasers.

The controller is compatible with all laser diode and monitor diode pin configurations, as well as our two-tab C-mount QCL and ICL packages. It features a constant current (CC) or constant power (CP) mode. Most common temperature sensors can be used, and the ITC4005QCL can be adapted to different thermal loads via a digital PID controller. It offers an auto-tune PID function or separate control of the P, I, and D parameters. For more details about these features, please see the More Info tab.

The ITC4005QCL is controlled via front panel keys and intuitive operation menus on a large and easy-to-read graphic LCD display (see the Display tab for sample screens). Additionally, the ITC4000 Series can be controlled by a SCPI-compatible USB Interface. A higher setting and measurement resolution is offered via USB operation since the front panel resolution is limited by the resolution of the display. Various outputs and a digital I/O port offer many control and connectivity options. The built-in function generator allows analog modulation of the laser output out of the box.

These controllers offer many advanced features such as Quasi-Continuous Wave (QCW) operation mode, easy auto-tune PID, and diverse laser and TEC element protection (see the More Info tab). The controller design also provides silent and power-efficient operation. These features make the ITC4005QCL an ideal choice for safe and secure operation of medium- to high-power QCLs, ICLs, and laser diodes either in the lab or in production environments.


Item #aITC4005QCL
Current Control Range 0 to 5 A
Compliance Voltage 20 V
Photocurrent Measurement Ranges 2 mA / 20 mA
QCWb Mode Pulse Width Range 100 µs to 1 s
QCWc Repetition Rate Range 1 ms to 5 s (0.2 to 1000 Hz)
TEC Current Range -15 to +15 A
TEC Compliance Voltage >15 V
TEC Output Power (Max) >225 W
Temperature Range (Max) -55 to +150 °Cc
Supported Temperature Sensors Thermistors, Pt100, Pt1000, AD590, AD592, LM335, LM235, LM135, LM35
  • For complete specifications, see the Specs tab.
  • Quasi-Continuous Wave
  • The applicable control range depends on the sensor parameters.


Connector Cables

Item #CAB4005CAB4001CON4005CON4001
  CAB4005 CAB4000 CON4005 CON4001
Description Standard Laser Diode Cable Standard TEC Element Cable 13W3 Male and Female
Connector Kit (One Each)
17W2 Male and Female
Connector Kit (One Each)
Max Current 5 A 5 A 20 A 20 A
Connector Type 13W3 Male to DB-9 Male 17W2 Male to DB-9 Female Loose 13W3 Connectors,
Male and Female
Loose 17W2 Connectors,
Male and Female


Our Mission is to accelerate the advancement of optical technology for precision measurements and their applications from the table tops of research laboratories to standard use in communication and high technology industries. Our aim is to serve our customers. Our hope is to create a place for highly skilled people in an open environment

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