Analytical modeling of the gas-filling dynamics in photonic crystal fibers

Abstract

We present useful expressions predicting the filling time of gaseous species inside photonic crystal fibers. Based on the theory of diffusion, this gas-filling model can be applied to any given fiber geometry or length by calculating diffusion coefficients. This was experimentally validated by monitoring the filling process of acetylene gas in several fiber samples of various geometries and lengths. The measured filling times agree well, within AE15%, with the predicted values for all fiber samples. In addition, the pressure dependence of the diffusion coefficient was experimentally verified by filling a given fiber sample with acetylene gas at various pressures. Finally, optimized conditions for gas-light interaction are determined by considering the gas flow dynamics in the design of microstructured fibers for gas detection and all-fiber gas cell applications.

First investigation of an all-fiber versatile laser frequency reference at 2 µm for CO2 lidar applications

“…During the filling process the value of the peak transmission was observed to saturate after about 80 minutes, indicating that the HC-PCF core was completely filled with CO 2 . This duration is in good agreement with the filling time of 78 minutes that was estimated using an analytical diffusion model developed at EPFL [10] and the parameters of the HC-PCF. Fig.…”

All-fiber versatile laser frequency reference at 2 μm for CO2 space-borne lidar applications

“…The required filling time can be fairly well estimated using an analytical model based on the theory of diffusion that takes into account the fiber geometry and length, as well as the gas parameters [29]. The parameters listed in Table 2 for the CO 2 molecule have been considered in the model computation.…”

“…7). The sensitive area of the photodiode placed directly at the output of the MM fiber pigtail was Table 2 Properties of the carbon dioxide molecule used in the model of the HC-PCF cell filling time [29] chosen large enough to collect the entire illumination exiting the output connector of the MM fiber (with 50-μm core diameter). Therefore, the effect of speckle noise arising at the fiber output was totally negligible as the speckle pattern is integrated over the entire beam section.…”

Gas-filling dynamics of a hollow-core photonic bandgap fiber for nonvacuum conditions

“…These studies have been limited to single-gas injection and closed-loop configurations [6]. Existing gas delivery schemes have been limited to low-gas flows (i.e., less than 5 psi) [7], single-gas delivery, or vacuum conditions [8]. Gas loading systems based on pressure-driven filling have been reported in [9,10].…”