An in-situ optical system based on photoacoustic approach with Supercontinuum laser source (SCL) for monitoring of acetylene (C2H2) has been proposed and demonstrated. The SCL has a broadband spectrum of 800–2800 nm. A bandpass filter with a bandwidth of 50 nm (FWHM) and center wavelength of 1525 nm was used for selecting the absorption wavelength of C2H2. Direct absorption spectroscopy (DAS) and Photoacoustic spectroscopy (PAS) output was monitored for different concentrations of C2H2. The minimum detection limit of PAS is found to be 105 times better than DAS. Simultaneous measurement of multiple gas species is also possible with the proposed optical sensor. © 2020, Springer Nature Singapore Pte Ltd.