Extruded tellurite antiresonant hollow core fiber for Mid-IR operation

Abstract

We report the first extruded tellurite antiresonant hollow core fibers (HC-ARFs) aimed at the delivery of mid-infrared (Mid-IR) laser radiation. The preform extrusion fabrication process allowed us to obtain preforms with non-touching capillaries in a single step, hence minimizing thermal cycles. The fibers were fabricated from in-house synthetized tellurite glass (containing Zn, Ba and K oxides) and co-drawn with a fluorinated ethylene propylene (FEP) polymer outer layer to improve their mechanical properties and protect the glass from humidity. The fabricated HC-ARFs transmit in the Mid-IR spectral range from 4.9 to 6 µm. We measured losses of ∼8.2, 4.8 and 6.4 dB/m at 5 µm, 5.6 µm and 5.8 µm, respectively in two different fibers. These losses, which are dominated by leakage mostly arising from a non-uniform membrane thickness, represent the lowest attenuation reported for a tellurite-based HC-ARF to date. The fibers present good beam quality and an M2 factor of 1.2. Modelling suggests that by improving the uniformity in the capillary membrane thickness losses down to 0.05 dB/m at 5.4 µm should be possible, making this solution attractive, for example, for beam delivery from a CO laser.

A Review of Antiresonant Hollow-Core Fiber-Assisted Spectroscopy of Gases

“…ARHCFs are fabricated with the aid of the commonly used stack-and-draw technique [30]. In majority, these fibers are drawn down from high purity fused silica glass (e.g., Suprasil F300) [8], however, due to the high material absorption of this material at the wavelengths above 5 µm, several successful attempts have been reported on fabricating ARHCFs from borosilicate and telluride glass allowing these fibers to efficiently guide light beyond the aforementioned wavelength range [28,31]. Thanks to the unique structure and light guidance properties, ARHCFs deliver better performance and versatility in comparison to other types of HCFs, especially in the area of fiber-aided gas sensing.…”

“…Nevertheless, due to its unique structure, the fiber was characterized by an exceptional immunity to bending, which indicates the excellent robustness, compactness, and versatility of the ARHCF-based absorption cells delivering a few meters long interaction path. The operational wavelength range of the ARHCF-based gas sensors was significantly increased with the development of borosilicate-glass-and telluride-glass-based fibers [28,31], which broke the barrier of 5 µm wavelength range, where the attenuation of silica glass increases rapidly [3,42]. Thanks to this unique feature, the ARHCF technology could be implemented in NO detectors.…”

“…It is expected that the size of the sensor could be further reduced by decreasing the size of the electronic and optomechanical components used together with tightened bending of the fiber-forming the absorption cell. The authors indicated that the obtained MDL was less The operational wavelength range of the ARHCF-based gas sensors was significantly increased with the development of borosilicate-glass-and telluride-glass-based fibers [28,31], which broke the barrier of 5 µm wavelength range, where the attenuation of silica glass increases rapidly [3,42]. Thanks to this unique feature, the ARHCF technology could be implemented in NO detectors.…”

Gas fiber lasers may represent a breakthrough in creating powerful radiation sources in the mid-IR

“…To date, tellurite hollow core fibers have been developed by an extrusion and draw approach. In 22 the fiber losses of 4.8 and 6.4 dB/m were measured at 5.6 and 5.8 µm, respectively. According to the authors 22 , this gives hope that in the near future it will be possible to fabricate tellurite hollow core optical fibers with sub 1–2 dB/m loss anywhere in the technologically important spectral region between 4.5 and 6.5 µm.…”

“…In 22 the fiber losses of 4.8 and 6.4 dB/m were measured at 5.6 and 5.8 µm, respectively. According to the authors 22 , this gives hope that in the near future it will be possible to fabricate tellurite hollow core optical fibers with sub 1–2 dB/m loss anywhere in the technologically important spectral region between 4.5 and 6.5 µm. In 23 the authors reported the fabrication of a hollow core fiber drawn from chalcogenide glass 3D printed preform.…”