Interband Cascade Lasers (ICLs) are semiconductor lasers that have output in the mid-infrared (MIR) region of the spectrum, generally between 3 and 6 μm. Operating on the principle of interband transitions (as opposed to intersubband transitions in quantum cascade lasers), the structure of these bands is designed for the desired output wavelength.

Due to their MIR output, ICLs are commonly used in gas sensing. Many atmospheric gases have their major absorption features in this range, including carbon dioxide, methane, and water vapor.

ICLs come in two common varieties, Fabry-Pérot and distributed feedback (DFB). Fabry-Pérot type ICLs have a larger emission bandwidth (up to 50 nm from center), whereas the DFB type have a much narrower emission bandwidth (as low as 0.1 nm from center).

Their output power is on the order of milliwatts, with low electrical pumping requirements (operating voltages less than 10 V, and operating current less than 1 A).

Wavelength Electronics offers multiple laser drivers that meet the required specifications for driving ICLs.

The QCL Series Drivers, in both OEM and benchtop instrument packaging, offer the lowest noise operation available. Utilizing patented¹ circuitry, these drivers produce the lowest current noise density of any commercially available driver. For more information about effectively using these low-noise drivers, see AN-LD08: Manage Grounding to Minimize Noise with the QCL Drivers and AN-LD09: Troubleshooting Low Noise Systems.

If small packaging is a requirement, choose an LDD P Series, PLD Series, MPL Series, or FL500 laser driver, depending on the current and voltage requirements.

For further simplification of an experimental setup, the LDTCxx20 Series offer integrated laser driver and temperature control into one small unit.

In addition to the current and voltage requirements, these drivers also include features to ensure safe operation of the laser, and safety of the user. The table below outlines suitable Wavelength drivers.

PRODUCT	MAX CURRENT	MAX VOLTAGE	DATASHEET
QCL500 OEM*	500 mA	16 V
QCL500 OEM(+)	500 mA	16 V
QCL500 LAB*	500 mA	20 V
QCL1000 OEM*	1000 mA	16 V
QCL1000 OEM(+)	1000 mA	16 V
QCL1000 LAB*	1000 mA	20 V
LDD200 P	200 mA	12 V
LDD400 P	400 mA	12 V
PLD200	200 mA	28 V
PLD500	500 mA	28 V
MPL250	250 mA	6 V
MPL500	500 mA	6 V
FL500	500 mA	20 V
LDTC0520	500 mA	12 V
LDTC1020	1000 mA	12 V

*These drivers are based on grounded anode operation with the cathode connected to a negative voltage. Consult the product datasheet for more information regarding proper setup with these drivers.

For questions regarding the suitability of any product for driving an ICL, please contact Wavelength Tech Support (techsupport@www.teamwavelength.com) for free and responsive assistance.

¹Covered by U.S. Patents 6,696,887; 6,867,644; and 7,176,755. Licensed from Battelle Memorial Institute.