Dispersive Fourier Transform Spectrometer Based on Mode-Locked Er-Doped Fiber Laser for Ammonia Sensing

Dispersive Fourier transform (DFT) has emerged as a powerful technique, enabling the transformation of spectral information from an optical pulse into a temporal waveform. This advancement facilitates the implementation of absorption spectroscopy using a single-pixel photodetector and a pulsed laser, particularly effective when operating on wavelengths near the absorption lines of the gas under study. This paper introduces a DFT-spectrometer employing a mode-locked tunable fiber laser with the central wavelength of 1531.6 nm. We demonstrate fast acquisition NH3 absorption spectroscopy with a 0.2 nm spectral resolution, achieved through the utilization of the HITRAN database for estimating ammonia concentrations. Alongside the successful demonstration of NH3 absorption spectroscopy, we explore practical limiting factors influencing the system's performance. Furthermore, we discuss potential avenues for enhancing sensitivity and spectral resolution, aiming to enable more robust and accurate gas sensing applications.