VCSEL measurements and characterization for gas sensing

Abstract

The paper presents the results of measurements and analysis of parameters and characteristics of Vertical Cavity Surface Emitting Laser (VCSEL) Diode to use in gas detectors on the basis of the tunable diode laser spectroscopy method. Precise absorption spectra were obtained to determine the optimal wavelengths for gas sensing. The measurement results showed that the possibility of increasing the output power of VCSEL by enlarging the diameter of the tunnel junction being limited by the increase of the number of modes in the emission spectrum. The analysis of the encapsulated VCSEL modules had demonstrated high SMRS (above 40 dB), high temperature stability of the emission wavelength (dλ/dT≈ 0.05–0.08 nm/K), possibility of continuous change of emission wavelength with operation current, which allows efficient use of VCSEL for ammoniac detection by TDLS method.