Fiber Ring Laser Intra-cavity Absorption Spectroscopy for Gas Sensing: Analysis and Experiment

Abstract

Fiber ring laser based intra-cavity absorption spectroscopic sensor has great potential for high sensitivity gas detection. Using the rate equations and propagation equations, we investigated theoretically factors that affect the sensitivity of such fiber ring laser sensors and determined the optimal design parameters and conditions for significant enhancement of the system sensitivity. Experiments have been conducted to determine the sensitivity enhancement performance. The results showed a factor of 25 ~ 30 in sensitivity enhancement in the experimental system, agreeing well with the theoretical expectations. Experiments on acetylene detection have also been carried out and the results showed that the ring cavity significantly increases the signal absorption and that high sensitivity can be obtained for gas detection. .

Graphene-PVA saturable absorber for generation of a wavelength-tunable passively Q-switched thulium-doped fiber laser in 2.0µm

“…The output repetition rate in this work is superior to that of the work in [34] and [45], with the maximum repetition rate achieved by those works is only between 16.0 kHz and 26.0 kHz. Only in [33] the repetition rate has a slightly higher value of 53.0 kHz, compared to the 36.29 kHz obtained in this work. The same is also true for the pulse width in [45], with minimum value of only 9.8 µs is obtained.…”

“…The same is also true for the pulse width in [45], with minimum value of only 9.8 µs is obtained. Although the maximum pulse energy of 11.03 nJ obtained in this work is lower than the 85.0 nJ and the 70.0 nJ obtained in [33] and [34] respectively, it is still comparable to that was obtained in [45]. The comparisons made in table 1 show that our Q-switching operation hold the advantage, given that the wavelength of the system can be tuned to several wavelengths.…”

“…Two micron wavelength fiber lasers, where thulium doped fiber is used as the gain medium, have recently become the focus of increasing research interest due to their ability to generate lasing outputs that have high absorption coefficient in water and gases, sparking substantial interest in sensing applications [28][29][30] and also in the area of spectroscopy [31][32][33][34]. Repasky et al [34] for example demonstrated the use of a laser with wavelengths from 2.000 to 2.005 µm to efficiently determine the concentration of carbon dioxide in a localised atmosphere to monitor for leakage.…”

2µm mode-locked thulium-doped fiber laser using Mach–Zehnder interferometer tuning capability

“…Two-micron wavelength fiber lasers have recently become the focus of increasing research interest due to their ability to generate a lasing output with a high absorption coefficient in water and gases, making them high-potential candidates for sensing applications [1] compared to other used near-and mid-infrared wavelengths [2]. Furthermore, two-micron lasers are also 'eye-safe', sparking substantial interest for employment in industrial use, precision medical applications [2,3], sensing [4][5][6][7] and spectroscopy [8][9][10].…”

Impact of Booster Section Length on the Performance of Linear Cavity Brillouin-Erbium Fiber Laser

“…Multiwavelength Fiber laser (MFL) has been the focus of many researchers in the last two decades due to its potential application in dense wavelength division multiplexing (DWDM) communication systems [1], optical sensors [2] and spectroscopy [3]. Since then, numerous works have been reported where the aim is to improve lasing threshold, number of generated Stokes lines and tuning range [4,5].…”