Interband Cascade Lasers

Interband Cascade Lasers (ICL) are a mid-IR light source with emission in the 2.7-3.9 µm range, which is important in particular for hydrocarbon detection and other gases of interest. With lower dissipation than traditional QCLs some ICL lasers are available in TO-66 housing in addition to the standard TO3 and HHL.


ICL-DFB lasers are single mode lasers able to emit a single wavelength at a time. They can be tuned within a range of typically 10 cm-1; there exists a variety of modulation schemes which can be used for different purposes. DFB lasers are mostly used for spectroscopy. They are currently available at the selected frequencies of 2853 cm-1, 2898 cm-1, 2913 cm-1 and 2946 cm-1 (respectively 3505 nm, 3450 nm, 3433 nm and 3394nm).

ICL devices are based on a different design principles than QCL, which cause some technical differences. The main difference is that the current, voltage and power dissipation are much lower which allows for easy integration in smaller packages and systems.The output is also typically lower. The emitted light is also linearly polarized with TE polarization; in a HHL package this translates in an horizontal polarization.

You can find the complete specifications of ICL-DFB lasers in this Product Factsheet.

Key Features

  • Continuous Wave
  • Single-Mode Spectrum
  • Tunable source
  • Low Dissipation
  • High Beam Quality
  • Narrow Linewidth


This sample spectrometric measurement shows a typical ICL-DFB laser centered around 2937.8 cm-1 being used to measure absorption through a 5 cm gas cell with with CH4 at 5 mbar of pressure. The blue line shows the expected transmission as extracted from HITRAN data and the red line shows the experimental results, showing good agreement and showcasing the narrow linewidth of the laser.