An approach of superluminescent light emitting diode (SLED)-based multiple-gas sensing and O vapor) is proposed and demonstrated by using an absorption spectroscopy technique for emission monitoring process) applications. Such process normally occurs at temperature range of 250–400 C where significant interference effect due to O vapor is expected. Hence, measuring multiple gases and eliminating cross-interference effect is of great importance in sensing trace gases. In this study, an SLED-based sensor with center emission wavelength of 1530-nm region is chosen to measure the concentrations of pure and O vapor by probing its overtone and combination bands present in this region. Detection limit for the gas accounted in the case of aqua-ammonia (undiluted) is estimated to be 120 ppm m. A novel approach of introducing an open-space etalon in the path of the SLED beam is also proposed and demonstrated for adequate isolation from interfering species and improving the detection limit. By using an etalon with a free spectral range of 104 GHz and tuning it to appropriate wavelength, detection limit of about 22 ppmm is attained for gas sensing in the presence of O vapor.