Room-temperature continuous-wave external cavity interband cascade laser tunable from 3.2 to 3.6 µm

Area of Science:

• Optoelectronics
• Laser Physics
• Semiconductor Devices

Background:

• Interband cascade lasers (ICLs) are crucial for mid-infrared applications.
• External cavity (EC) configurations enable wavelength tunability in semiconductor lasers.

Purpose of the Study:

• To investigate and report on the wide tuning capabilities of external cavity interband cascade lasers (EC-ICLs).
• To demonstrate continuous-wave (CW) operation of EC-ICLs at room temperature.

Main Methods:

• Utilized antireflection coated ICL gain chips.
• Employed a diffraction grating in a Littrow configuration for wavelength tuning.
• Operated the lasers in continuous-wave mode at room temperature (293 K).

Main Results:

• Achieved a wide tuning range of 313 cm^-1 (3.22 to 3.58 µm).
• Demonstrated a maximum output power of 13 mW.
• Measured a minimum threshold current of 62 mA at peak gain.

Conclusions:

• EC-ICLs offer significant wavelength tunability at room temperature.
• The demonstrated performance is promising for applications requiring tunable mid-infrared sources.
• Further optimization of gain chip design and cavity parameters can enhance performance.