Proceedings Article | 24 November 2021
KEYWORDS: Quantum cascade lasers, Gases, Absorption, Wavelength tuning, Laser systems engineering, Light sources, Mid-IR, Laser sources, Laser development
Quantum cascade laser (QCL) is a new type of unipolar semiconductor laser. It has the advantages of narrow line width, tunable wavelength, high output power, etc. The QCL is widely used in gas detection, medical diagnosis, petrochemical industry, environmental pollution prevention and control, communications and military fields. Because it is difficult to cover the absorption peaks of multiple gases, a single QCL laser cannot detect and identify multiple different gases at the same time. Therefore, beam combination of multiple QCL laser is a feasible solution to achieve simultaneous online detection of multiple gases. This paper demonstrates a multi-wavelength QCL laser system based on spatial parallel beam combination. Four QCL lasers with wavelengths of 1274.70 cm-1, 1606.68 cm-1, 1831.84 cm-1, and 2226.18 cm-1 are integrated. The power of a single QCL reaches more than 100mW, and the total output power reaches 0.81W. By controlling the temperature of the heat sink, the wavelength tuning ranges of 9.65nm, 6.54nm, 7.54nm, and 10.45nm can be achieved respectively. The temperature tuning coefficients are 0.85nm/℃, 1.06 nm/℃, 1.25 nm/℃, 0.80 nm/℃, and the wavelength tuning accuracy is 85pm, 106pm, 125pm, 80pm. The system designed in this paper can simultaneously detect the gas whose absorption peak locates at the above four wavelength ranges, and can also customize a QCL laser with matched wavelength according to the absorption peak of the gas to be measured, which has good scalability.
